Nuclear and Radiation Studies Board to review it independently. As a result of the Army’s request, the National Research Council convened the Committee on Toxicologic and Radiologic Effects from Exposure to Depleted Uranium During and After Combat, which prepared the present report.
The committee’s task was to review the toxicologic, radiologic, epidemiologic, and toxicokinetic data on DU and to assess the Capstone Report on toxicologic and radiologic risks to soldiers posed by exposure to DU. It was to consider health-hazard and environmental reports prepared by such organizations as the World Health Organization, the UN Environment Programme (for the postconflict Balkans), the International Atomic Energy Agency, the Agency for Toxic Substances and Disease Registry, and the UK Royal Society. The committee was also to identify relevant data deficiencies and offer recommendations for future research.
The Capstone Report considered three kinds of scenarios of exposure to DU in combat and postcombat settings. Level I exposure involved soldiers who were in vehicles at the time of perforation with DU munitions or first responders who entered the struck vehicles shortly thereafter to rescue the injured. Five scenarios were considered for level I exposure: crew exiting a struck vehicle within 1 min, 5 min, 60 min, or 120 min or first responders entering a vehicle within 5 min to rescue injured crew members and exiting within 10 min. Level II exposure involved workers who were in or around vehicles containing DU fragments and particles at times after the event but were not in the vehicles at the time of impact and did not immediately enter vehicles after they were struck. Level III exposure was brief or incidental and was considered negligible.
The Army conducted an aerosol study to characterize the DU exposures that were likely to have occurred in combat situations. The study involved shooting DU munitions into stripped-down Abrams tanks and a Bradley fighting vehicle and collecting samples to estimate time-integrated concentrations of DU in the air in the vehicles. Intakes of DU were estimated, and biokinetic models were used to predict the chemical and radiologic doses to body tissues.
Overall, the committee found the methods and results of the Capstone exposure assessment to be appropriate and well done. To verify the exposure-assessment results, the committee made its own estimates on the basis of data developed largely outside the Capstone program. Using older datasets on the aerosol characteristics of the dusts and fumes produced when a DU penetrator strikes a hard target, the committee found that its estimated intakes in level I exposures were within a factor of 2 of the Capstone results. For levels II and III exposures, the committee calculated exposure rates resulting from surface contamination resuspended in the air and from incidental ingestion by using stan-