Q. What is depleted uranium?
A. Depleted uranium
is what is left over when most of the highly radioactive types (isotopes) of uranium are removed for use
as nuclear fuel or nuclear weapons. The depleted uranium used in armor-piercing munitions and in enhanced
armor protection for some Abrams tanks is also used in civilian industry, primarily for radiation shielding
and aircraft balance control.
Q. What makes depleted uranium a potential hazard?
A. Depleted uranium is a heavy metal that is also slightly
radioactive. Heavy metals (uranium, lead, tungsten, etc.) have chemical toxicity
properties that, in high doses, can cause adverse health effects. Depleted uranium
that remains outside the body can not harm you.
A common misconception is that radiation is depleted uranium's primary hazard.
This is not the case under most battlefield exposure scenarios. Depleted uranium is approximately
40 percent less radioactive than natural uranium. Depleted uranium emits alpha and beta particles,
and gamma rays. Alpha particles, the primary radiation type produced by depleted uranium, are blocked
by skin, while beta particles are blocked by the boots and battle dress utility uniform (BDUs)
typically worn by Service members. While gamma rays are a form of highly-penetrating energy , the
amount of gamma radiation emitted by depleted uranium is very low. Thus, depleted uranium does not
significantly add to the background radiation that we encounter every day.
When fired, or after "cooking off" in fires or
explosions, the exposed depleted uranium rod poses an extremely low radiological
threat as long as it remains outside the body. Taken into the body via
metal fragments or dust-like particles, depleted uranium may pose a long-term
health hazard to personnel if the amount is large. However, the amount
which remains in the body depends on a number of factors, including the
amount inhaled or ingested, the particle size and the ability of the particles
to dissolve in body fluids.
Q. Were any studies on the health effects of depleted
uranium ever conducted prior to the onset of the Gulf War? What were the
findings of those studies?
A. The health effects of uranium have been studied extensively for over
50 years. This is relevant because chemically, DU has the same properties as natural uranium,
while being 40% less radioactive. While natural and depleted uranium are considered chemically
toxic, they are not considered a radiation hazard. In May 1989 the Department of Health and Human
Services' Agency for Toxic Substances and Disease Registry published
Toxicological Profile for Uranium reviewing and summarizing the key uranium health effects
literature. This document was updated in September 1999.
The Department of Defense has comprehensively studied the environmental fate
of depleted uranium both before and after the Gulf War. Burn tests and other evaluations performed
under simulated battlefield conditions indicated that the health risks associated with the battlefield
use of depleted uranium were minimal and could be reduced even more by simple, field-expedient measures,
especially, avoidance of depleted uranium-contaminated vehicles and sites.
Q. There are reports from the Balkans and Iraq of individuals
recovering the DU penetrators. Are these hazardous?
A. Depleted uranium penetrators are only one of many possible hazards
on the battlefield. Civilians and soldiers are strongly discouraged from recovering souvenirs,
particularly spent ammunition, from the battlefield.
Fortunately, DU is only mildly radioactive emitting alpha and beta particles,
and gamma rays. Alpha particles, the primary radiation type produced by DU, are blocked by
skin, while beta particles are blocked by clothing and shoes. While gamma rays are a form of
highly-penetrating energy, the amount of gamma radiation emitted by DU is very low. The
risk of chemical toxicity is also minimal because there is little likelihood that sufficient
quantities of DU could be inhaled or ingested to cause a heavy metal concern.
Q. What has the Defense Department done to protect future
generations of service members from accidental exposure to depleted uranium?
A. The Department of Defense is fully aware of its responsibility
for the safe use of depleted uranium. Since the Gulf War, the DoD has dramatically stepped
up its emphasis on increasing soldier and leader awareness of the hazards associated with the
battlefield use of depleted uranium. The Deputy Secretary of Defense has ordered the Service
Chiefs to ensure that DU awareness training is incorporated into their general military training
programs. The U.S. Army's Training and Doctrine Command published Training Support Packages for
general DU awareness training and certain specialty training in July 1999. The Marine Corps also
uses a three-level DU training program. Both the Marines and Navy use a service-specific variant
of the Army's DU Awareness Training video. The Air Force program calls for all personnel on
mobility status to receive DU awareness training and has incorporated DU awareness guidance in the
Nuclear, Biological, and Chemical handbook carried by all deploying personnel. Complete
implementation of the various training programs is underway. The Office of the Special Assistant will
continue to monitor the status of the Services' DU training efforts.
Q. In what way has the DoD attempted to track service
members exposed to depleted uranium during the 1990-1991 Gulf War?
A. We have categorized the DU exposure scenarios into three levels
based on their relative exposures, and have conducted testing to estimate the maximum
exposure that could be associated with those scenarios. The levels of possible exposure
are described more fully on the
Medical Follow-Up page of this website, which also contains links to DoD policy on
management of exposures. Level I is the highest exposure group, soldiers who were in, on,
or near combat vehicles at the time they were struck by depleted uranium rounds, and soldiers
who entered these vehicles immediately afterwards to perform combat rescue. This exposure level
also includes personnel who have been struck by DU fragments. Depleted uranium metal fragments
have struck a number of US soldiers, and some of these still have embedded DU fragments. Others
are believed to have inhaled or ingested DU particles, or had DU dust contaminate their wounds.
The voluntary Veterans Affairs (VA) DU Medical Follow-up program in Baltimore remains the most
important source for identifying potential adverse health effects in those friendly-fire victims who
have embedded DU fragments, or who may have inhaled significant quantities of DU particles. About
one fourth of the Level I exposed individuals who have been evaluated by the VA still carry DU
fragments in their bodies, and some of those with embedded fragments have elevated levels of urine
uranium more than ten years after the Gulf War. None of the individuals with DU fragments have
developed kidney problems, leukemia, bone or lung cancers, or any other uranium-related adverse
outcomes. No birth defects have been reported in their children. As a result, there is no reason
to believe that other exposed Service members have any elevated risk to their health due to their
DU exposures. However, to be cautious, the DoD and the VA continue to medically follow veterans with
high-level DU exposures to ensure there are no long-term health effects associated with these ongoing
DU exposures. References to some of the research articles reporting follow-up results on these
Service members and veterans can be found through Research Projects and Publications in this website,
and going to "DeployMed ResearchLink" for
Medical Research Publications: Environmental & Occupational Health\Depleted Uranium.
Level II exposures comprise soldiers who worked in and around combat vehicles (mainly US
vehicles that were struck by friendly fire munitions) and as many as 600 personnel who took part in the
clean up after the fire at Camp Doha, where DU munitions were burned in a fire. These exposures resulted
in significantly lower estimated intakes of DU than the Level I exposures. The radiation estimates were
less than the 0.1 rem per year guideline for members of the general public and much less than the 5 rem
per year limit for radiation workers. The chemical exposure estimates were also well below the chemical
Level III is an "all others" category for personnel whose incidental exposure to DU
particles were very brief and are highly unlikely to have resulted in any medically significant exposure
taking place. This group includes curious personnel who entered Iraqi equipment or personnel down wind
from vehicles that burned after being struck by depleted uranium rounds. This group's estimated
exposures were minimal.
A multidisciplinary team from the US Army Aberdeen Test Center, US Army Armament Research,
Development, and Engineering Center, USACHPPM, Batelle Memoral Institute, Pacific Northwest National
Laboratory, Los Alamos National Laboratory, and the Lovelace Respiratory Research Institute conducted
a study of the anticipated exposures under various scenarios, as well as the possible health effects or
risks resulting from these exposures. The results were reported in the Capstone DU Project, comprised
of two phases, the Capstone DU Aerosols Study, and the Capstone DU Human Health Risk Assessment. The
Capstone DU Project realistically assessed possible exposures and risks for personnel in Levels I, II,
and III. Both a summary fact sheet and the original study
are available. The Capstone DU Aerosols Study confirmed the value of ventilation in reducing possible
exposures to DU aerosols inside vehicles struck by DU munitions, and clearly showed that simply getting
out of DU-struck vehicles provided a way to significantly reduce exposures. The Capstone Depleted
Uranium Human Health Risk Assessment determined there would be little or no impact on the health of
service members who breathe in depleted uranium (DU) dust particles while inside tanks or other
vehicles hit by DU munitions.
More information on combat exposures is also available at Tab O of "Environmental
Exposure Report", Depleted Uranium in the Gulf (II), or "Depleted Uranium-Human Exposure Assessment
and Health Risk Characterization in Support of the Environmental Exposure Report
'Depleted Uranium in the Gulf' of the Office of the Special Assistant to the Secretary of Defense
for Gulf War Illnesses, Medical Readiness and Military Deployments (OSAGWI)".
Q. What are the health effects of contact with unfired
depleted uranium munitions or unperforated (intact) armor on the various
weapons systems, such as the Abrams Heavy Tank?
A. No adverse health effects are expected from such contact. Unfired depleted
uranium munitions are encased in thin metal jackets that seal in alpha and beta particles. The amount
of gamma emissions from DU is very low and falls well below regulatory health and safety limits.
Similarly, depleted uranium panels used in tank armor pose no health risk because the depleted uranium
is sealed inside several inches of regular steel armor. Alpha radiation, which is the major concern for
internalized depleted uranium, is not an external concern because alpha radiation does not penetrate
the outer layers of skin. The second source of radiation is from the depleted uranium rounds stored on
board the tank. While soldiers are exposed to an increased level of radiation from the stored munitions,
the cumulative exposure levels for tank crewmembers are within applicable guidelines. Since depleted
uranium munitions are only used in combat, only forward-deployed vehicles are routinely uploaded with
depleted uranium munitions.
While it is impossible to evaluate all potential exposure scenarios, each of the major
weapon systems have been fully evaluated and all of the routine exposures are well within exposure
guidelines. In fact, radiation levels measured inside the turret of an Abrams Heavy Armor Tank are
below background levels measured outside the turret because armor shields the tank occupants from cosmic
and terrestrial radiation sources. Crewmembers have their overall radiation exposure reduced by working
inside the tank.
The most frequently cited example of radiation exposure is holding a bare penetrator rod.
The penetrator rods in the 120mm, 105mm and 30mm rounds are shielded which prevents direct contact with
the actual penetrator rod of intact rounds. But even when holding a bare penetrator rod, an individual
could hold the rod for 250 hours before reaching the extremity or skin limit of 50 rem.
Q. The European press in particular has been raising
concerns of increased rates of leukemia in European troops that have been
stationed in the Balkans. Can exposure to DU be the cause of these cases
A. It is highly unlikely that exposure to DU ammunition would cause leukemia.
The Agency for Toxic Substances and Disease Registry of the U.S. Department of Health and Human
Services stated in its Toxicological Profile for Uranium,"[n]o human cancer of any type has ever been seen
as a result of exposure to natural or depleted uranium." A
1999 RAND study concluded, "there are no peer-reviewed published reports of detectable increases
of cancer or other negative health effects from radiation exposure to inhaled or ingested natural
uranium at levels far exceeding those likely in the Gulf." Exposures in the Balkans should be no more
than those in the Gulf.
After the media reports in early 2001, nations who had deployed peacekeepers to the
Balkans have begun medical monitoring and epidemiological studies. The objective of the studies is to
determine whether there is an increase in medical problems in troops who served in the region when
compared to troops who did not. To date, none of these studies have found a connection between DU
exposure and leukemia or any other pathology. The United Nations and other international organizations
also have conducted environmental surveys in Bosnia-Herzegovina and Kosovo. These surveys consistently
have reported no widespread DU contamination and no current impact on the health of the general
population or deployed personnel.
Leukemias following high doses of radiation peak in frequency five to seven years after
exposure. Media accounts of leukemia cases and deaths within months of return from the Balkans are not
consistent with current scientific understanding of the time course of radiation-induced leukemia.
Q. Press accounts have indicated the presence of trace levels of plutonium
and other contaminants in DU that are indicative of recycled nuclear fuel.
Is this true? How did these contaminants get in the DU and does it change
your evaluation of the health hazards associated with DU exposure?
A. Yes, trace levels of
transuranics have been found in DU. The Department of Energy operated three
gaseous diffusion plants (Paducah, Kentucky; Portsmouth, Ohio; and Oak Ridge, Tennessee) where they
enriched uranium for nuclear weapons and power plants; creating depleted uranium as a by-product.
Some or all of these plants received recycled uranium extracted from spent nuclear fuels in the '50s,
'60s, '70s, and '80s. Uranium extracted from spent nuclear fuels included low levels of transuranics,
including americium, neptunium, and plutonium, technetium-99, and uranium-236. The gaseous diffusion
process concentrates these contaminants in the enriched uranium and decreases the levels in the
depleted uranium so that only trace quantities remain. The radioactive contaminants increase the
radiation dose from theDU itself by less than 1 percent, which is considered insignificant.
In March 2001, DOE reported the results of a two-year recycled uranium study that
concluded the transuranic content in depleted uranium was very low. The DOE data are consistent
with U.S. Army testing of the DU used in armor plate for the Abrams Heavy Tank, which concludes the
radioactive contaminants contribute less than a one percent increase in the radioactivity from DU
itself. Various NATO countries and the United Nations Environment Programme (UNEP) recently recovered
penetrators in the Balkans and tested them for the level of contaminants. Their findings are consistent
with DOE/DoD findings. The UNEP concluded that the transuranics have no significant impact on the
overall radioactivity or the health risk. These contaminant levels are in the parts per billion range.
A part per billion is approximately equivalent to one second in 31.7 years.
Q. With all of the medical and environmental concerns over DU, why hasn't
DoD found a substitute for DU?
A. Each weapon system that uses DU has undergone extensive developmental
testing and evaluation. As part of that process, DoD evaluates possible alternative metal alloys
considering operational requirements and medical/environmental impacts. As improvements have been
made in the "hardness" of armored vehicles, tests have demonstrated that DU offers superior
performance to all other alloys.
DoD must also evaluate the environmental and medical consequences of exposure to any
new alloy. Uranium has an advantage in this arena over several candidate materials because of the
extensive database on radiological and chemical properties of uranium. While some candidate replacement
alloys may not be radioactive, they are not necessarily less toxic to humans.
Q. Were any depleted uranium health effects studies conducted after the Gulf War?
What were the findings of those studies?
A. The two main areas that were not adequately addressed before the Gulf War were:
The medical implications of embedded DU fragments in people and inhalation exposure
estimates for friendly fire incidents, recovery activities, and incidental contact scenarios.
These are recognized weaknesses that are being addressed. The
December 19, 2000 Environmental
Exposure Report, Depleted Uranium in the Gulf (II) includes the Army's latest health risk exposure
estimates for various Gulf War exposure scenarios. Health risk estimates for DU-contaminated vehicle
recovery and incidental contact scenarios indicate that these exposures were well within safety
standards. Because of gaps in data pertaining to uranium oxide dust levels inside DU-struck vehicles,
exposure estimates for personnel inside DU-struck vehicles at the time of impact, or immediately
afterwards, were based on conservative assumptions. These estimates for this highest exposed group
indicated that medical follow-up was warranted. DoD is currently in the process of conducting
additional live-fire testing in order to further refine the exposure estimates for those troops in or
around vehicles when they were hit by DU munitions. It is important to note that over 60 friendly-fire
victims have been evaluated by the voluntary VA DU Medical Follow-up Program. Aside from the problems
associated with their traumatic injuries, to date, this follow-up program has attributed no illness
or other harmful effects in the evaluated veterans to DU.
The voluntary Veterans Affairs DU Medical Follow-up Program began in 1993-1994 with the
medical evaluations of 33 friendly-fire DU-exposed veterans, many with embedded DU fragments. An
additional 29 of the friendly-fire victims were added to the surveillance program in 1999. In 1998,
the program was expanded to include Gulf War veterans who may have been exposed to DU through close
contact with DU munitions, inhalation of smoke containing DU particulate during a fire at the Doha
depot or while entering or salvaging vehicles that were hit with DU projectiles. The published results
of these medical evaluations indicate that the presence of embedded DU fragments is the only scenario
predictive of a high urine uranium value, and those with embedded DU fragments continue to have elevated
urine uranium levels ten years after the incident. It is unlikely that an individual without embedded
DU fragments would have an elevated urine uranium level, and consequently any uranium-related health
effects. Those individuals with normal urine uranium levels now are unlikely to develop any
uranium-related toxicity in the future, regardless of what their DU exposure may have been in the Gulf
War. Those individuals with elevated levels of urine uranium ten years after the Gulf War have not
developed kidney abnormalities, leukemia, bone or lung cancer, or any other uranium-related adverse
outcome. The DU Medical Follow-up Program will continue to monitor those individuals with elevated
urine uranium levels to enable early detection of any adverse health effects due to their continued
exposure to DU.
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