TAB L -- Research Report Summaries

This tab lists chronologically some of the major research on military use of depleted uranium (DU). Though not all-inclusive, this list indicates the depth and breadth of research conducted to date.

  1. Hanson, Wayne C., Ecological Considerations of Depleted Uranium Munitions, LA-5559. Los Alamos, NM: Los Alamos Scientific Laboratory of the University of California, June 1974.

  1. Hanson, Wayne C., J.C. Elder, H.J. Ettinger, L.W. Hantel, and J.W. Owens, Particle Size Distribution of Fragments from Depleted Uranium Penetrators Fired Against Armor Plate Targets, LA-5654. Los Alamos, NM: Los Alamos Scientific Laboratory of the University of California, October 1974.

  1. Environmental Assessment Depleted Uranium (DU) Armor Penetrating Munitions for the GAU-8 Automatic Cannon, Development and Operational Test and Evaluation, Office of the Air Force Surgeon General (AF/SGPA), April 1975.
  1. Elder, J.C., M.I. Tillery, and H.J. Ettinger, Hazard Classification Test of GAU-8 Ammunition by Bonfire Cookoff with Limited Air Sampling, Number LA-6210-MS, Informal Report, Los Alamos, NM: Los Alamos Scientific Laboratory of the University of California, February 1976.

  1. Hanson, Wayne C. and Felix R. Miera, Jr., Long-Term Ecological Effects of Exposure to Uranium, LA-6269, Los Alamos, NM: Los Alamos Scientific Laboratory of the University of California, July 1976.

  1. Prado, Captain Karl L., External Radiation Hazard Evaluation of GAU-8 API Munitions, TR 78-106, Brooks Air Force Base, TX: United States Air Force Occupational and Environmental Health Laboratory, 1978.

  1. Patrick, Michael A., and J.C. Cornette, Morphological Characteristics of Particulate Material Formed from High Velocity Impact of Deleted Uranium Projectiles with Armor Targets, AFATL-TR-78-117, Eglin AFB, FL, United States Air Force Armament Laboratory, Environics Office, November 1978.

  1. Stolfi, Dr. R., Dr. J. Clemens and R. McEachin, Combat Damage Assessment Team A-10/GAU-8 Low Angle Firings Versus Individual Soviet Tanks, February-March 1978, Volume 1, United States Air Force/56780/2 February 1979.

  1. Bartlett, W.T., R.L. Gilchrist, G.W.R. Endres, and J.L. Baer, Radiation Characterization and Exposure Rate Measurements from Cartridge, 105-mm, APFSDS-T, XM774, PNL-2947, Richland, WA: Battelle Pacific Northwest Laboratory, November 1979.

  1. Gilchrist, R.L., J.A. Glissmyer, and J. Mishima, Characterization of Airborne Uranium from Test Firings of XM774 Ammunition, PNL-2944, Richland, WA, Battelle Pacific Northwest Laboratory, November 1979.

  1. Gilchrist, R.L., P. W. Nickola, J. A. Glissmeyer, and J. Mishima, Characterization of Airborne Depleted Uranium from April 1978 Test Firings of the 105mm, APFSDS-T, M735E1 Cartridge, PNL-2881, Richland, WA: Battelle Pacific Northwest Laboratory, 1979 (initial release), June 1999 (publication date).

  1. Davitt, Richard P., A Comparison of the Advantages and Disadvantages of Depleted Uranium and Tungsten Alloy as Penetrator Materials, Tank Ammo Section Report No. 107, Dover, NJ: US Army Armament Research and Development Command, June 1980.

  1. Ensminger, Daniel A. and S.A. Bucci, Procedures to Calculate Radiological and Toxicological Exposures from Airborne Release of Depleted Uranium, TR-3135-1, Reading, MA: The Analytic Sciences Corporation, October 1980.

  1. Elder, J.C. and M.C. Tinkle, Oxidation of Depleted Uranium Penetrators and Aerosol Dispersal at High Temperatures, LA-8610-MS, Los Alamos, NM: Los Alamos Scientific Laboratory of the University of California, December 1980.

  1. Chambers, Dennis R., Richard A. Markland, Michael K. Clary, and Roy L. Bowman, Aerosolization Characteristics of Hard Impact Testing of Depleted Uranium Penetrators, Technical Report ARBRL-TR-02435, Aberdeen Proving Ground, MD: US Army Armament Research and Development Command, Ballistic Research Laboratory, October 1982.

  1. Hooker, C.D., D.E. Hadlock, J. Mishima, and R.L. Gilchrist, Hazard Classification Test of the Cartridge, 120mm, APFSDS-T, XM829, PNL-4459, Richland, WA: Battelle Pacific Northwest Laboratory, November 1983.

  1. Mishima, J., M.A. Parkhurst, R.L. Scherpelz, and D.E. Hadlock, Potential Behavior of Depleted Uranium Penetrators Under Shipping and Bulk Storage Accident Conditions, PNL-5415, Richland, WA: Battelle Pacific Northwest Laboratory, March 1985.

  1. Wilsey, Edward F. and Ernest W. Boore, Draft Report: Radiation Measurement of an M1A1 Tank Loaded with 120mm M829 Ammunition. Aberdeen Proving Ground, MD: US Army Ballistic Research Laboratory, July 1985.

  1. Magness, C. Reed, Environmental Overview for Depleted Uranium, CRDC-TR-85030, Aberdeen Proving Ground, MD: Chemical Research Development Center, October 1985.

  1. Scherpelz, R.I, J. Mishima, L.A. Sigalla, and D.E. Hadlock, Computer Codes for Calculating Doses Resulting from Accidents Involving Munitions Containing Depleted Uranium, PNL-5723, Richland, WA: Battelle Pacific Northwest Laboratory, March 1986.

  1. Haggard, D.L., et al., Hazard Classification Test of the 120mm, APFSDS-T, M829 Cartridge: Metal Shipping Container, PNL-5928, Richland, WA: Battelle Pacific Northwest Laboratory, July 1986.

  1. Hooker, C.D. and D.E. Hadlock, Radiological Assessment Classification Test of the 120mm, APFSDS-T, M829 Cartridge: Metal Shipping Container, PNL-5927, Richland, WA: Battelle Pacific Northwest Laboratory, July 1986.

  1. Life Cycle Environmental Assessment for the Cartridge, 120mm: APFSDS-T, XM829, Picatinny Arsenal, NJ: US Army Armament Research, Development and Engineering Center, Close Combat Armament Center, December 12, 1988.

  1. Parkhurst, M.A. and K.L. Sodat, Radiological Assessment of the 105mm, APFSDS-T, XM900E1 Cartridge, PNL-6896, Richland, WA: Battelle Pacific Northwest Laboratory, May 1989.

  1. Wilsey, Edward F. and E.W. Bloore, M774 Cartridges Impacting Armor-Bustle Targets: Depleted Uranium Airborne and Fallout Material, BRL-MR-3760, Aberdeen Proving Ground, MD: Ballistic Research Laboratory, May 1989.

  1. Erikson, R.L., C.J. Hostetler, J.R. Divine, and K.R. Price, Environmental Behavior of Uranium Derived from Depleted Uranium Alloy Penetrators, PNL-2761, Richland, WA: Battelle Pacific Northwest Laboratory, June 1989.

  1. Fliszar, Richard W., Edward F. Wilsey, and Ernest W. Bloore, Radiological Contamination from Impacted Abrams Heavy Armor, Technical Report BRL-TR-3068, Aberdeen Proving Ground, MD: Ballistic Research Laboratory, December 1989.

  1. Hadlock, D.E. and M.A. Parkhurst, Radiological Assessment of the 25mm, APFSDS-T XM919 Cartridge, PNL-7228, Richland, WA: Battelle Pacific Northwest Laboratory, March 1990.

  1. M.A. Parkhurst, J. Mishima, D.E. Hadlock, and S.J. Jette, Hazard Classification and Airborne Dispersion Characteristics of the 25mm, APFSDS-T XM919 Cartridge, PNL-7232, Richland, WA: Battelle Pacific Northwest Laboratory, April 1990.

  1. Kinetic Energy Penetrator Long Term Strategy Study (Abridged), Final Report, Picatinny Arsenal, NJ: US Army Production Base Modernization Activity, July 24, 1990.

  1. Jette, S.J., J. Mishima, and D.E. Haddock, Aerosolization of M829A1 and XM900E1 Rounds Fired Against Hard Targets, PNL-7452, Richland, WA: Battelle Pacific Northwest Laboratory, August 1990.

  1. Munson, L.H., J. Mishima, M.A. Parkhurst, and M.H. Smith, Radiological Hazards Following a Tank Hit with Large-Caliber DU Munitions, Draft Letter Report, Richland, WA: Battelle Pacific Northwest Laboratory, October 9, 1990.

  1. Memorandum to SMCAR-CCH-V from SMCAR-SR, Radiological Hazards in the Immediate Areas of a Tank Fire and/or Battle Damaged Tank Involving Depleted Uranium, Letter Report, Picatinny Arsenal, NJ: December 4, 1990.

  1. Mishima, J., D.E. Hadlock, and M.A. Parkhurst, Radiological Assessment of the 105mm, APFSDS-T, XM900E1 Cartridge by Analogy to Previous Test Results, PNL-7764, Richland, WA: Battelle Pacific Northwest Laboratory, July 1991.

  1. Parkhurst, M.A., Radiological Assessment of M1 and M60A3 Tanks Uploaded with M900 Cartridges, PNL-7767, Richland, WA: Battelle Pacific Northwest National Laboratory, July 1991.

  1. Life Cycle Environmental Assessment for the Cartridge, 105mm: APFSDS-T, XM900E1, Picatinny Arsenal, NJ: US Army Armament Research, Development and Engineering Center, Close Combat Armament Center, August 21, 1991.

  1. Life Cycle Environmental Assessment for the Cartridge, 120mm: APFSDS-T, XM829A2, Picatinny Arsenal, NJ: US Army Production Base Modernization Activity, February 2, 1994.

  1. Parkhurst, M.A. and R.I. Scherpelz, Dosimetry of Large Caliber Cartridges: Updated Dose Rate Calculations, PNL-8983, Richland, WA: Battelle Pacific Northwest Laboratory, Reissued, June 1994.

  1. Parkhurst, M.A., G.W.R. Endres, and L.H. Munson, Evaluation of Depleted Uranium Contamination in Gun Tubes, PNL-10352, Richland, WA: Battelle Pacific Northwest Laboratory, January 1995.

  1. Parkhurst, M.A., J.R. Johnson, J. Mishima, and J.L. Pierce, Evaluation of DU Aerosol Data: Its Adequacy for Inhalation Modeling, PNL-10903, Richland, WA: Battelle Pacific Northwest Laboratory, December 1995.

  1. Kerley, C.R., et al., Environmental Acceptability of High-Performance Alternatives for Depleted Uranium Penetrators, ORNL/TM-13286, Oak Ridge, TN: Oak Ridge National Laboratory, August 1996.

  1. Parkhurst, M.A., J. Mishima, and M.H. Smith, Bradley Fighting Vehicle Burn Test, PNNL-12079, Richland, WA: Battelle Pacific Northwest National Laboratory, February 1999.

  1. Final Soil Report, Depleted Uranium and Isotopic Uranium Analysis Results, CHPPM Project No. 47-EM-7120-99, Aberdeen Proving Ground, MD: US Army Center for Health Promotion and Preventive Medicine, August 20, 1999.

Summaries

  1. Hanson, Wayne C. Ecological Considerations of Depleted Uranium Munitions, LA-5559, Los Alamos, NM: Los Alamos Scientific Laboratory of the University of California, June 1974.

This report concluded that expended DU munitions' major ecological hazard would be chemical toxicity rather than radiation. Because DU munitions are composed of alloys, the DU's mobility decreases substantially compared to natural uranium. However, the report stated that the chemical toxicity of expended DU to terrestrial ecosystems could not be ignored and must be seriously considered.

  1. Hanson, W.C., J.C. Elder, H.J. Ettinger, L.W. Hantel, and J.W. Owens, Particle Size Distribution of Fragments from Depleted Uranium Penetrators Fired Against Armor Plate Targets, LA-5654, Los Alamos, New Mexico: Los Alamos Scientific Laboratory of the University of California, October 1974.

One of the first scientific studies to evaluate the nature of particles generated during hard impact testing; researchers conducted five tests firing U-2/3 percent Ti 30mm (272 gram) penetrators against armor plate. The researchers analyzed the resulting respirable aerosol particle sizes with four eight-stage Anderson impactors. Two impactors collected samples from the chamber in front of the target and two impactors from the rear (i.e., exit) chamber. Researchers dismantled the 0.25m3 entrance and 0.27 m3 exit chambers after each shot and collected and processed the residual fragments through a US Standard Sieve Series with sieve fractions of <53, 53 to 105, 105 to 500, 500 to 2000, 2000 to 5660 and >5660 m fragments. The effective cutoff diameters for the 8 impactor stages were 11, 7, 4.7, 3.3, 2.1, 1.1, 0.65, and 0.43 m.

Researchers fired five shots. However, the first shot's data and half the data from the second and third shots were lost due to overloading of the impactor stages. Even though all tests were conducted at 0 obliquity and velocities that varied by only 2 percent between the minimum and maximum, the test results varied widely. The percentage of the penetrator recovered in the entrance chamber varied by over a hundredfold whereas the range in the exit chamber varied by only sixfold. Typically, about 80 percent of the total sample weight and uranium content occurred in the large fragment fraction from the exit chamber. The uranium content of the large fragments in the entrance chamber varied widely, perhaps indicating the entrance chamber armor plate disintegrated. The report stated the mass distribution was 1:4 between the entrance and exit chambers "indicating that much of the DU penetrator pierced the armor plate unfragmented." "Compounded samples of the six size fractions from the exit chamber contained nearly three times the uranium found in similar aggregate samples from the entrance chamber."

  1. Environmental Assessment, Depleted Uranium (DU) Armor Penetrating Munitions for the GAU-8 Automatic Cannon, Development and Operational Test and Evaluation, AF/SGPA, April 1975.

This was the US Air Force's GAU-8 Ammunition Program Environmental Assessment, covering manufacturing, transportation, storage, use, and disposal. The Report's conclusion was a finding of "no significant environmental impact."

  1. Elder, J.C., M.I. Tillery, and H.J. Ettinger, Hazard Classification Test of GAU-8 Ammunition by Bonfire Cookoff with Limited Air Sampling, LA-6210-MS, Informal Report. Los Alamos, NM: Los Alamos Scientific Laboratory of the University of California, February 1976.

On August 26, 1975, the Los Alamos Laboratory under contract to the US Air Force Armament Laboratory, Eglin AFB, FL tested the new 30mm armor piercing GAU-8 ammunition containing a DU core to establish its hazard classification. In addition to "fragment pattern scoring," testers conducted air sampling to evaluate the potential for creating airborne DU. The bonfire cook-off set off 180 live GAU-8 rounds. The test plan did not include measuring aerosol size characteristics and mass concentrations.

Analysis of the air sampling data concluded nothing beyond the obvious fact that DU aerosol was released. Of the 180 rounds, 179 (the exception being a shell base) remained within 400 feet of the bonfire. The DU penetrators lost a good deal of mass in the bonfire -- about 30 percent of the penetrators lost visually detectable amounts of DU. The remaining 70 percent escaped the high temperatures that normally turn DU into aerosol and ash. The report states, "Almost total dispersion of several penetrators to aerosol and ash illustrated the probable fate of any penetrator remaining in a high temperature region." In other words, in fires, the potential for DU aerosol dispersion is greater than in other scenarios.

  1. Hanson, Wayne C. and Felix R. Miera, Jr., Long-Term Ecological Effects of Exposure to Uranium, LA-6269, Los Alamos, NM: Los Alamos Scientific Laboratory of the University of California, July 1976.

This was one of the initial efforts to evaluate the ecological effects of releasing depleted uranium during explosives tests at selected sites at Eglin AFB, Florida, and Los Alamos Scientific Laboratory (LASL), Los Alamos, New Mexico. At Eglin, researchers collected samples adjacent to the target gun butts and 60, 120, 180, and 240 feet from the gun butts. At each location, a sample was collected from the top 5 centimeters (cm) of ground and from a depth of 5 to 10 cm. The gun butt samples averaged 800 ppm of uranium in the upper 5 cm interval, approximately 30 times more than in the 5 to 10 cm interval. The report stated this indicated "modest vertical movement of depleted uranium into the soil." Samples collected 60 feet from the gun butts indicated levels of 20 ppm and 2 ppm in the 0 to 5 and 5 to 10 cm intervals. Samples collected beyond 20 feet indicated near background levels of uranium or about 2.3 10 g/g (ppm).

Researchers also monitored residues at two Los Alamos explosives testing sites. Levels at the E-F Site averaged 2499 ppm uranium (natural and depleted uranium) in the upper 5 cm level and 1600 ppm in the 5 to 10 cm levels. Levels in the second test area were approximately 2.5 and 0.6 percent of the E-F site values. The report stated, "Important concentration differences with depth and distance from the detonation points were ascribed to the different explosive test designs peculiar to each area."

The report also cited average vegetative levels of 320 ppm of uranium at the E-F site in November 1974 versus 125 ppm in June 1975. By comparison, the levels in small mammals trapped in November contained a maximum of 210 ppm in the GI tract, 24 ppm in the pelt, and 4 ppm in the remaining carcass compared to 110, 50 and 2 ppm in similar samples in June 1975. The study stated that their data emphasize "the importance of resuspension of respirable particles in the upper few millimeters of soil as a contamination mechanism in several components of the ecosystem."

The report stated, "Soil analysis indicated that relatively large fragments as well as fine particulates from uranium explosive tests corrode readily and then migrate into the soil at variable rates. Weathering is apparently faster in the humid environment and porous soil at EAFB than at LASL."

  1. Prado, Captain Karl L., External Radiation Hazard Evaluation of GAU-8 API Munitions, TR 78-106, Brooks Air Force Base, TX: United States Air Force Occupational and Environmental Health Laboratory, 1978.

The study concluded typical field conditions met the protective standards for radiation contained in 10 CFR 20.105 with these provisos: "(1) Occupancy of any area 100 cm from any accessible surface of stored CNU-309/E containers by non-occupationally exposed personnel does not exceed a total of 1,000 hours per year, and that (2) the PGU-14/B cartridge is in a case when handled (if the cartridge is handled directly, the total contact time with the projectile surface should not exceed 180 hours per calendar quarter)."

  1. Patrick, Michael A., and J.C. Cornette, Morphological Characteristics of Particulate Material Formed from High Velocity Impact of Deleted Uranium Projectiles with Armor Targets, AFATL-TR-78-117, Eglin AFB, FL: United States Air Force Armament Laboratory, Environics Office, November 1978.

This early study attempted to examine gross morphological characteristics of particulates formed during hard impacts of DU penetrators. Although the Air Force performed this test, researchers used the Army's 105mm tank round, not the Air Force's 30mm DU penetrator. Some of the report's key conclusions include:

  1. Scanning electron microscopy revealed airborne particulates were primarily spherical, the surfaces of which were highly convoluted. Particles were at times comprised of partially overlapping, concave plates, formed as a result of polyfocal solidification. Extreme fracturing, particularly along the convoluted folds and plate lines, accounted for the apparent fragility associated with airborne particles of the rugose type. Under normal weathering conditions such particles could be expected to break up rapidly, thereby contributing to an increase in the total number of respirable-size particles.

  2. Particle disintegration would be further accelerated by the hollow nature of many of the spheres. Hollow particles, which are frequently thin-walled or perforated, are extremely vulnerable to weathering and thus subject to rapid deterioration.

  3. The elemental composition of individual particles was qualitatively determined by non-destructive x-ray spectroscopy. Airborne particles were comprised primarily of alloyed uranium and iron. Although the ratio of the two metals varied considerably among particles, the fact that alloying did occur is consistent with violent interaction between penetrator and target at impact.

  4. An unexpected phenomenon was the formation of ultrafine particles less than 0.1 m in diameter. These particles, generally observed adhering to the surfaces of larger particles, presumably were formed as a result of the extreme temperature achieved and the highly reactive nature of pyrophoric depleted uranium. These ultrafine particles exhibited an extreme tendency to coalesce, probably due to spontaneous diffusion charging. This coalescing tendency of particles, which were originally below the respirable size-range, is especially significant since it resulted in the formation of abundant agglomerates that fell within the respirable range.

  5. Particles isolated from soil samples near the target area, in addition to uranium and iron, frequently contained appreciable amounts of silicon, aluminum, and/or tungsten. Fusion with both silicon and aluminum had been anticipated as a result of interaction with sand and clays within the soil. The presence of tungsten was due to contamination of the target site from previous test firings of high-density penetrators employing that material.

  6. Results show that appreciable quantities of respirable-size particles are released during use of these projectiles. Although particles are initially formed over an extremely broad range, eventual weathering of large particles together with coalescence of ultrafine particles combine to increase the potential total number of particulates within the respirable range.

  1. Stolfi, Dr. R., Dr. J. Clemens, and R. McEachin, Combat Damage Assessment Team A-10/GAU-8 Low Angle Firings Versus Individual Soviet Tanks, February-March 1978, Volume 1, Air Force/56780/February 2, 1979.

In this test an A-10 aircraft attacked two combat-loaded individual Soviet T-62 tanks in five missions totaling seven passes; technicians rehabilitated the two vehicles after each pass. The aircraft were seldom higher than 200 feet in altitude; firings were initiated between 2768 and 4402 feet and terminated at ranges of 1587 to 3055 feet at dive angles of 1.8 to 4.4. The bursts ranged from 120 to 165 rounds.

Altogether 93 DU rounds struck the tanks during the seven passes, including no impacts on one pass. The ratio of impacts to rounds fired was 0.10. Of the 93 impacts, 17 penetrated the armored envelopes for a ratio of perforations to impacts of 0.18. The report noted many of the side or rear impacts that did not penetrate the armor nonetheless extensively damaged the tanks' exterior suspension components, whereas all the rounds that hit the tanks' front caused minimal damage. These results reinforced the strategy of attacking tanks from the side or rear to optimize damage potential.

  1. Bartlett, W.T., R.L. Gilchrist, G.W.R. Endres, and J.L. Baer, Radiation Characterization and Exposure Rate Measurements from Cartridge, 105mm, APFSDS-T, XM774, PNL-2947, Richland, WA: Battelle Pacific Northwest Laboratory, November 1979.

The Joint Technical Coordinating Group for Munitions Effectiveness Working Group on Depleted Uranium Munitions recommended this as one of three studies in its initial 1974 DU environmental assessment. This study focused on the health physics problems associated with assembling, storing, and using 105mm APFSDS-T XM774 ammunition. The report concluded, "Radiation levels associated with the XM774 ammunition are extremely low. The photon emissions measured did not exceed a maximum whole-body or critical organ exposure of 0.26 mR/hr. Even if personnel were exposed for long periods to the highest levels of radiation measured, it is doubtful that their exposure would reach 25 percent of the maximum permissible occupational dose listed in Title 10 of the Code of Federal Regulations, Part 20."

  1. Gilchrist, R.L., J.A. Glissmyer, and J. Mishima, Characterization of Airborne Uranium from Test Firings of XM774 Ammunition, PNL-2944, Richland, WA: Battelle Pacific Northwest Laboratory, November 1979.

This was the last of three studies the Joint Technical Coordinating Group for Munitions Effectiveness (JTCG/ME) recommended in the late 1970s; the other two were "Radiological and Toxicological Assessment of an External Heat (Burn) Test of the 105mm Cartridge, APFSDS-T, XM774" and "Radiation Dose Rate Measurements Associated with the Use and Storage of XM774 Ammunition." The purpose of this test was to obtain the data necessary to evaluate the potential risk to human health from exposure to airborne DU. The data included:

  1. Size distribution of airborne DU.
  2. Quantity of airborne DU.
  3. Dispersion of airborne DU from the target vicinity.
  4. Amount of DU deposited on the ground.
  5. Solubility of airborne DU compounds in lung fluid.
  6. Oxide forms of airborne and fallout DU.

The study extensively assessed total and respirable DU levels above and downwind of the targets, fallout and fragment deposition around the target, and cloud volume, estimated by analyzing high-speed movies of the smoke generated by the penetrator impact. Although technical problems occurred during the test (e.g., filter overload, etc.), the researchers drew these conclusions:

  1. Each test firing generated approximately 2.4 kg of airborne DU.

  1. Approximately 75 percent of the airborne DU was U3O8 and 25 percent was UO2.

  1. Immediately after the test, about 50 percent of the airborne DU was respirable, of which 43 percent was dissolved in simulated lung fluid within seven days. After seven days the remaining DU was essentially insoluble.

  1. While respirable-sized airborne particles predominantly were U3O8, they also included iron and traces of tungsten, aluminum, and silicon compounds.

  1. The report stated, "Measurement of airborne DU in the target vicinity (within 20 ft.) after a test firing showed that personnel involved in routinely changing targets could be exposed to concentrations exceeding recommended maximums. This may have resulted in part from mechanical resuspension of DU from the soil or other surfaces."

The researchers encountered numerous problems in sampling for total particulates, which contributed to their conclusion the average fraction of the penetrator that aerosolized was 70 percent. These problems included:

  1. The particulate samplers became clogged and the flow rates dropped to zero, requiring researchers to estimate the sampling time;

  1. The number of fallout trays near the target was inadequate to determine the amount of DU deposited on the ground; and

  1. Researchers could not fully evaluate the cloud volumes because of inadequate films of the cloud.

Despite the technical problems encountered during the test, 70 percent is frequently cited as the average amount of penetrator aerosolized during hard impact.

  1. Gilchrist, R.L., P. W. Nickola, J. A. Glissmeyer, and J. Mishima, Characterization of Airborne Depleted Uranium from April 1978 Test Firings of the 105mm, APFSDS-T, M735E1 Cartridge, PNL-2881, Richland, WA: Battelle Pacific Northwest Laboratory, 1979 (initial release), June 1999 (publication date).

Battelle first released this report to the US Army in 1979 but the project office decided not to publish it then. Due to the current interest in the historical Depleted Uranium testing program and the uncertainty associated with the frequently-cited 70 percent aerosolization figure, in June 1999 Battelle decided to publish this report. This information is extracted from Battelle's summary:

This report is a follow-up to the hard target impact testing of the M774 and takes advantage of the field experience and difficulties faced in that 1977 test to improve test conditions and sample collection. This second test, conducted in 1978 at Ford's Farm within Maryland's Aberdeen Proving Ground, was more successful in characterizing the impact cloud plumes, as well as measuring time-integrated concentrations (TIC) with time since impact and particle size distributions. Uncertainties so prominent in the M774 report are considerably reduced in this M735E1 evaluation.

In this test, the 105-mm M735E1 cartridges were fired at a series of three armor plate targets located about 200 meters away. The impact and penetration of the projectiles caused a shower of fragments and considerable airborne particulates. This projectile assembly contained a 2.2-kg DU core. Specific objectives of the test included investigating:

During this test, the uranium concentration was reduced faster under wet surface conditions. Additionally, it appeared that the concentration of the cloud was probably uniform and representative at 2 second post-shot. Using cloud volume and airborne mass, the airborne fraction of the penetrators could be calculated.

The overall results of the test are as follows:

Video documentation (high-speed motion pictures), used to estimate cloud volume as a function of time, and meteorological measurements of wind speed and direction conducted by site personnel assisted in interpreting data.

Aerosols from Hard Target Impact

Airborne Fraction

Particle Size Distribution

Post-Shot Concentrations

17 to 28%

2.1-m MMAED with hi-vol monitor; 5.8-m MMAED with low-vol monitor Above MPC (278 g/m3) for 5 min at target and remained elevated for 15 min with dry surface, less with wet surface
  1. Davitt, Richard P., A Comparison of the Advantages and Disadvantages of Depleted Uranium and Tungsten Alloy as Penetrator Materials, Tank Ammo Section Report No. 107, Dover, NJ: US Army Armament Research and Development Command, June 1980.

This report provides an excellent history of the logic behind the Army's decision to use DU as a kinetic energy, armored-piercing munition. DU's final selection over tungsten was based on several reasons, including the lower initial cost of the penetrator itself and its better overall performance. DU and tungsten were rated even for "producibility." Tungsten had the advantage for safety, environmental concerns, and deployment.

  1. Ensminger, Daniel A., and S.A. Bucci, Procedures to Calculate Radiological and Toxicological Exposures from Airborne Release of Depleted Uranium, TR-3135-1, Reading, MA: The Analytic Sciences Corporation, October 1980.

This report described the models for assessing radiological and toxicological exposures from airborne DU dispersions under given release conditions -- particularly APFSDS-T (Armor-Piercing, Fin-Stabilized, Discarding Sabot-Tracered) XM774 and M735A1 rounds.

  1. Elder, J.C., and M.C. Tinkle, Oxidation of Depleted Uranium Penetrators and Aerosol Dispersal at High Temperatures, LA-8610-MS, Los Alamos, NM: Los Alamos Scientific Laboratory of the University of California, December 1980.

This early test evaluated the consequences of exposing DU penetrators to various thermal conditions ranging from 500 C to 1,000 C in different atmospheres for two to four hours. The tests' general conclusions were:

  1. DU aerosols with respirable-sized particles are produced when penetrators are exposed to temperatures above 500 C for one-half hour or more.

  1. Exposing the penetrators to sustained fires, forced drafts and temperature cycling enhanced the production of oxide and aerosol.

  1. Since the penetrators themselves are not flammable, complete oxidation required adequate fuel and a fire longer than four hours.

  1. Chambers, Dennis R., Richard A. Markland, Michael K Clary, and Roy L. Bowman, Aerosolization Characteristics of Hard Impact Testing of Depleted Uranium Penetrators, Technical Report ARBRL-TR-02435, Aberdeen Proving Ground, MD: US Army Armament Research and Development Command, Ballistic Research Laboratory, October 1982.

The Nuclear Regulatory Commission (NRC) required this early documentation to support indoor, confined testing of 105 and 120mm kinetic energy DU rounds. NRC initially approved the test firing of 10 rounds to verify the integrity of the test facility; then it approved firing 20 DU penetrators to characterize the aerosol generated by their impact with an armor target. The study results contradicted Battelle's previous study for the XM774, which indicated up to 70 percent of the DU penetrator aerosolized on impact. In this study, approximately 3 percent of the penetrator aerosolized 2 to 3 minutes after impact, and accounting for error, it was highly unlikely more than 10 percent aerosolized. The test data were consistent with previous test data for small-caliber ammunition. For the aerosolized particulates, the mass mean diameter was 1.6 micrometers and approximately 70 percent were fewer than 7 micrometers, considered the upper range of DU's respirable particulates. The study raised many questions about the nature of aerosols generated by hard-impact testing of DU penetrators.

  1. Hooker, C.D., D.E. Hadlock, J. Mishima, and R.L. Gilchrist, Hazard Classification Test of the Cartridge, 120mm, APFSDS-T, XM829, PNL-4459, Richland, WA: Battelle Pacific Northwest Laboratory, November 1983.

The purpose of this test was to determine the behavior of the XM829 cartridge when subjected to detonation of an adjacent XM829 cartridge and a sustained hot fire. The test concluded that detonating an XM829 cartridge in one container would not cause the immediate detonation of XM829 cartridges in adjacent cartridges. But if a fire starts and continues to burn, adjacent cartridges may ignite, scattering debris up to 40 feet. A mass analysis for the two experiments conducted under this project showed at least 80 percent of the cartridge's mass was recovered in the 1982 test and 100 percent in the 1983 test. No DU contamination was detected in samples from the sand taken from ground zero. Analysis of the filters from seven high-volume air samplers also indicated airborne uranium levels remained at natural background levels. The report noted, "Great care was taken during this time to prevent the residue from being scattered by winds and that under different conditions these values could vary." An analysis of the respirator canisters also revealed no measurable DU levels.

  1. Mishima, J., M.A. Parkhurst, R.I. Scherpelz, and D.E. Hadlock, Potential Behavior of Depleted Uranium Penetrators under Shipping and Bulk Storage Accident Conditions, PNL-5415, Richland, WA: Battelle Pacific Northwest Laboratory, March 1985.

This project's purposes were twofold: to characterize DU oxide samples' particle size, morphology, and lung solubility from 120mm M829 DU rounds exposed to an external heat test and to conduct a literature search on "uranium oxidation rates, the characteristics of oxides generated during the fire, the airborne release as a result of the fire, and the radiological/toxicological hazards from inhaled uranium oxides."

The test results indicated a maximum of 0.6 percent by weight of the DU oxide generated was in the respirable range (i.e., less than 10 m m Aerodynamic Equivalent Diameter) and the respirable fraction of the oxide was insoluble (i.e., 96.5 percent had not dissolved within 60 days). The study concluded DU oxides formed during burning should be classified as insoluble (Class Y–dissolution half-times in the lung of more than 100 days).

  1. Wilsey, Edward F., and Ernest W. Boore, Draft Report: Radiation Measurement of an M1A1 Tank Loaded with 120-MM M829 Ammunition, Aberdeen Proving Ground, MD: US Army Ballistic Research Laboratory, undated.

The Project Manager, M1A1 Abrams Tank System, US Army Tank and Automotive Command, supported this test. The tank was loaded with 40 M829 120mm rounds to evaluate crew radiation exposure levels. "Preliminary results of the radiation exposures to M1A1 tank crews were well within the Nuclear Regulatory Guidelines for the general population and there was no undue radiation hazard when the tank was fully loaded with M829 rounds."

  1. Magness, C. Reed, Environmental Overview for Depleted Uranium, CRDC-TR-85030, Aberdeen Proving Ground, MD: Chemical Research & Development Center, October 1985.

This overview of DU describes its relationship to natural uranium, its commercial and military applications, and its long-term effects on man and the environment. The Army wrote this report to fulfill the relevant background information requirements for its documentation, detailed in Army Regulation (AR) 200-2.

  1. Scherpelz, R.I., J. Mishima, L.A. Sigalla, and D.E. Hadlock, Computer Codes for Calculating Doses Resulting from Accidents Involving Munitions Containing Depleted Uranium, PNL-5723, Richland, WA: Battelle Pacific Northwest Laboratory, March 1986.

The report described the Army's computer modeling, which was created to determine whether to impose an exclusion zone around an accident site, where to locate a boundary, if any, and whether the potential effects further downwind would be significant or trivial based on the incident's characteristics, the actual munitions involved, and the munitions' packaging.

  1. Haggard, D.L., et al., Hazard Classification Test of the 120-MM, APFSDS-T, M829 Cartridge: Metal Shipping Container, PNL-5928, Richland, WA: Battelle Pacific Northwest Laboratory, July 1986.

This followed up the Hazard Classification Test summarized in PNL 4459 (Report 16 above), which was conducted with a wooden shipping container. This follow-up test was conducted to evaluate a new PA-116 metal shipping container. The report's conclusions were:

  1. Igniting a round in a metal shipping container by way of an external source did not cause the detonation of the entire package contents.
  2. Igniting one round surrounded by other rounds did not cause sympathetic detonation of the other rounds.
  3. Igniting the cartridges' propellant with a sustained fire caused individual rounds to explode. These explosions caused perceptible blast pressure pulses up to 20 feet away.
  4. The individual explosions blew cartridge and shipping container fragments into the air. The penetrators were recovered within 20 feet of the fire. Most of the fragments fell within 200 feet. Two fragments were recovered between 300 to 600 feet from the fire.
  5. Four of the 12 penetrators from the fire test showed evidence of oxidation. One penetrator core had oxidized almost completely to oxide powder.

The test also revealed these radiological aspects:

  1. About 9.5 percent of the total DU in the 12 cores was converted to oxide during the fire.
  2. The oxide was predominantly U3O8.
  3. The fraction of generated oxide aerodynamically small enough to be suspended in air and carried by the wind was 0.002 to 0.006 (0.2 percent to 0.6 percent).
  4. The fraction of generated oxide small enough to be inhaled was about 0.0007 (0.07 percent).
  5. The solubility of the DU oxide in simulated lung fluid indicated 96 percent was essentially insoluble, four percent dissolved in the fluid within 10 days.
  6. During the test, winds were relatively calm. "Air monitors (detection limit of 1m g DU) set up to intercept downwind DU aerosol detected no DU on their filters and tended to confirm that there was no significant airborne DU oxide."

The study concluded, "The minute quantity of oxide that was of respirable size and the calm winds limited the downwind disposal and posed no biological hazard to cleanup crews or others in the area."

  1. Hooker, C.D. and D.E. Hadlock, Radiological Assessment Classification Test of the 120-MM, APFSDS-T, M829 Cartridge: Metal Shipping Container, PNL-5927, Richland, WA: Battelle Pacific Northwest Laboratory, July 1986.

A follow-up study to a 1983 study evaluating potential health problems when shipping and storing M829 cartridges in wooden containers, this assessment evaluated radiation levels when packaging the M829 in a metallic container. Study results include the following:

  1. The M829 components effectively shield out the predominant nonpenetrating radiation emitted from the bare penetrator; the 1.0-MeV photons resulting from the decay of the 234mPa can penetrate both the projectile components and metal container.
  2. The radiation levels emanating from the assembled M829 cartridge are no different from the 1983 study, and the slightly higher radiation measurements at the package surface are due to the reduced distance between the penetrator and the outer package surfaces.
  3. The radiation levels associated with the M829 ammunition do not present a significant potential hazard to personnel handling and storing the ammunition.
  4. Measured with field-use-exposure-rate instruments, the radiation levels at the single shipping container's surface do not exceed 0.5 mR/hr; and the M829 shipping package satisfies all other 49 Code of Federal Regulations 173.421 and 173.42 criteria. The package therefore qualifies for shipment as "excepted from specification package, shipping paper and certification, marking and labeling requirements;" however, the inner or outer package must bear the word "Radioactive."
  5. The ammunition prepared for shipment must be certified as acceptable for transportation by having a notice enclosed in or on the package, included with the packing list, or otherwise forwarded with the package. This notice must include the name of the co-signer and the statement, "This package conforms to the conditions and limitations specified in 49 CFR 173.424 for articles manufactured from depleted uranium, UN 2909."
  1. Life Cycle Environmental Assessment for the Cartridge, 120MM: APFSDS-T, XM829, Picatinny Arsenal, NJ: US Army Armament Research, Development and Engineering Center, Close Combat Armament Center, December 12, 1988.

This was the initial Environmental Assessment (EA) for the M829 armor piercing round, which replaced the XM827 (the American analog of the German DM 13), the initial APFSDS-T round. The program included developing and testing four rounds: Target Practice (M831), High Explosive (M830), Armor Piercing (XM827), and Target Practice (M865). The EA incorporates all previous supporting studies on the M829 round (e.g., the radiological and hazard classification of the metal and wooden shipping containers). The EA's conclusion was a "Finding of No Significant Impact" for the M829's design, production, test and evaluation, deployment, and demilitarization.

  1. Parkhurst, M.A., and K.L. Sodat, Radiological Assessment of the 105mm, APFSDS-T, XM900E1 Cartridge, PNL-6896, Richland, WA: Battelle Pacific Northwest Laboratory, May 1989.

In this study the XM900E1 round was packaged in a PA-117 steel container. The report's conclusions are as follows:

  1. The components of the XM900E1 effectively shield out the predominant non-penetrating radiation emitted from the bare penetrator and significantly reduce the majority of the penetrating radiation. The 1.0 MeV photons resulting from the decay of 234mPa can penetrate both the components of the projectile and the metal canister but are somewhat reduced.
  2. Radiation levels associated with the XM900E1 ammunition do not present a significant potential hazard to personnel handling and storing the ammunition.
  3. Radiation levels at the surface of the single shipping package, measured with field-exposure-rate instruments, do not exceed 0.5 mR/hr and all other criteria specified by the US Department of Transportation (DOT) in 49 CFR 173.21 and 49 CFR 173.424 are satisfied by the XM900E1 shipping package.
  1. Wilsey, Edward F., and E.W. Bloore, M774 Cartridges Impacting Armor-Bustle Targets: Depleted Uranium Airborne and Fallout Material, BRL-MR-3760, Aberdeen Proving Ground, MD: Ballistic Research Laboratory, May 1989.

This study, one of several conducted on 105mm M774 ammunition, addresses only one objective -- the amount of DU aerosol and fallout around and downwind of the armor-bustle target. "Very little of the depleted uranium of the M774 penetrator left the immediate target area as an aerosol." The highest value -- regardless of the wind conditions -- was so low more than 1,400 such tests would have to be fired in a week before tolerance limits would begin to be reached. While the occupational Threshold Limit Value was exceeded when the cloud passed over the samplers, the time-weighted-average exposure for a 40-hour work week was only 0.07 percent of the occupational threshold limit.

  1. Erikson, R.L., C.J. Hostetler, J.R. Divine, and K.R. Price, Environmental Behavior of Uranium Derived From Depleted Uranium Alloy Penetrators, PNL-2761, Richland, WA: Battelle Pacific Northwest Laboratory, June 1989.

This report discusses factors affecting the conversion of DU metal to oxide, the subsequent influences on uranium's leaching and mobility through surface water and groundwater pathways, and growing plants' absorption of uranium. The Army undertook this project to attempt to understand uranium's environmental impact.

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