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Depleted uranium (DU) is uranium which contains mostly Uranium-238 and a reduced proportion of the isotope Uranium-235. It is a toxic byproduct of the enriching of natural uranium for use in nuclear reactors. DU is what is left over when most of the fissile radioactive isotopes of uranium are removed. The names Q-metal, depletalloy, and D-38, once applied to depleted uranium, have fallen into disuse.

As a radioactive byproduct otherwise requiring long term storage as low level nuclear waste, depleted uranium is an inexpensive but controlled material. It is useful for its extremely high density, which is only slightly less than that of tungsten. However, it has extremely poor corrosion properties, is pyrophoric (it will burn spontaneously when small particles are exposed to air), and since it, like all heavy metals, is toxic, as well as being radioactive, the facilities for processing it need to monitor and filter airborne particles.

Production and availability

Natural uranium metal contains about 0.71% U-235, 99.28% U-238, and about 0.0054% U-234. Depleted uranium contains only 0.2% to 0.4% U-235, the remainder having been removed and concentrated into enriched uranium through the process of isotope separation. The enrichment process does not create U-235 but merely separates the different isotopes of uranium. Therefore the process leaves large amounts of U-238 uranium as a byproduct. This byproduct is referred to as depleted uranium. For example producing 1 kg of 5% enriched uranium requires 11.8 kg of natural uranium, leaving about 10.8 kg of depleted uranium with 0.3% U-235.

• Depleted Uranium Fraction Calculator designed by: The WISE Uranium Project

The Nuclear Regulatory Commission (NRC) defines depleted uranium as uranium in which the percentage of the U isotope by weight is less than 0.711 percent (See 10 CFR 40.4.) The military specifications designate that the DU used by DoD contain less than 0.3 percent U (AEPI, 1995). In actuality, DoD uses only DU that contains approximately 0.2 percent U (AEPI, 1995).

World Depleted Uranium Inventory

Country	Organization	DU Stocks (in tons)	Reported
USA	DOE	480,000	2002
Russia	FAEA	460,000	1996
France	COGEMA	190,000	2001
UK	BNFL	30,000	2001
Germany	URENCO	16,000	1999
Japan	JNFL	10,000	2001
China	CNNC	2,000	2000
South Korea	KAERI	200	2002
South Africa	NECSA	73	2001
TOTAL		1,188,273	2002

Source: WISE Uranium Project

Health concerns

Soluble uranium salts are toxic, causing kidney damage in large doses and proven reproductive, neurological, and immunological harm in mammals. Soluble uranium salts are excreted in the urine, although some accumulation in lungs, bones, and soft tissues does occur. (Many uranium compounds are partially soluble, and some are insoluble.) The World Health Organisation has established a daily "tolerated intake" of soluble uranium salts for the general public of 0.5 μg/kg body weight (or 35 μg for a 70 kg adult): exposure at this level is not thought to lead to any significant kidney damage. However, these measures have not been designed to address reproductive toxicity.

The chemical toxicity of soluble uranium salts is about a million times greater than their radiological toxicity (Miller, et al. 2002.)

The dangers of exposure to depleted uranium combustion products has received widespread attention as a result of the use of DU munitions in the 1991 Gulf War and current conflicts. Peer-reviewed medical and scientific publications state that exposure to uranium is a cause of or contributing factor to Gulf War syndrome. The long-term effects on populations living in the areas in which DU munitions were used, also have caused some concern.

As of 2006, there is controversy over whether the production of uranium trioxide gas vapor from the use of DU munitions and other uranium combustion scenarios is a hazard. As the degree of risk is currently unexplored, this potential hazard is not listed in the MSDS (Material safety data sheet) for depleted uranium, and neither are reproductive, developmental, and immunotoxic risks.

Like all hexavalent uranium compounds (also called uranium(VI) compounds) the uranium combustion product uranium trioxide (also called UO₃ or uranyl oxide) is hazardous by inhalation, ingestion, and through skin contact. It is a poisonous, radioactive substance, which may cause shortness of breath, coughing, acute arterial lesions, and changes in the chromosomes of white blood cells and gonads leading to congenital malformations if inhaled.

In 2001, Doctors at the Serb-run hospital in Kosovska Mitrovica say the number of patients suffering from malignant diseases has increased by 200% since 1998. In the same year, The World Health Organization says there has been no reported increase in cancer among the civilian population in Kosovo. Similar findings exist in Bosnia.

Safety and environmental issues

About 95% of the depleted uranium produced to date is being stored as uranium hexafluoride, (D)UF₆, within steel cylinders in open air yards adjacent to enrichment plants. Each cylinder contains up to 12.7 tonnes (or 14 tons) of UF₆. In the U.S. alone, 560,000 metric tons of depleted UF₆ had accumulated by 1993. As of 2005, 686,500 metric tons in 57,122 storage cylinders were located near Portsmouth, Ohio, Oak Ridge, Tennessee, and Paducah, Kentucky. , The long-term storage of DUF₆ presents environmental, health, and safety hazards due to its chemical instability. When UF₆ is exposed to moist air, it reacts with the water in the air to produce UO₂F₂ (uranyl fluoride) and HF (hydrogen fluoride) both of which are highly soluble and toxic. Storage cylinders must be regularly inspected for evidence of corrosion and leakage. The estimated life time of the steel cylinders is measured in decades.

There have been several accidents involving uranium hexafluoride in the United States. The vulnerability of DUF₆ storage cylinders to terrorist attack is apparently not the subject of public reports. However, the U.S. government has been converting DUF₆ to solid uranium oxides for disposal. Such disposal of the entire DUF₆ inventory could cost anywhere from 15 to 450 million dollars.

Inhalation exposure risks

It should be noted that while this section addresses the health concerns of depleted uranium, all isotopes and compounds of uranium are toxic to various degrees and the information presented here may be generalised to apply to most of them.

Health effects of DU are determined by factors such as the extent of exposure and whether it was internal or external. Three main pathways exist by which internalization of uranium may occur: inhalation, ingestion, and embedded fragments or shrapnel contamination. Properties such as phase (e.g. particulate or gaseous), oxidation state (e.g. metallic or ceramic), and the solubility of uranium and its compounds influence their absorption, distribution, translocation, elimination and the resulting toxicity. For example, metallic uranium is relatively non-toxic compared to hexavalent uranium(VI) compounds such as uranyl nitrate. (See «Gmelin Handbuch der anorganischen Chemie» 8th edition, English translation, Gmelin Handbook of Inorganic Chemistry, vol. U-A7 (1982) pp. 300-322.)

Projectile DU munitions can cause substantial inhalation exposure risks. Those risks have been associated with a number of health concerns, some of which are controversial.

See also: Depleted uranium, incendiary projectile munitions

Early scientific studies usually found no link between depleted uranium and cancer, and sometimes found no link with increases in the rate of birth defects, but newer studies have, and have explaned the birth defect links. There is no direct proof that uranium causes birth defects in humans, but it induces them in several other species of mammals, and human epidemiological evidence is consistent with increased risk of birth defects in the offspring of persons exposed to DU.. Environmental groups and others have expressed concern about the health effects of depleted uranium, and there is significant debate over the matter. Some people have raised concerns about the use of this material, particularly in munitions, because of its proven mutagenicity , teratogenicity , in mice, and neurotoxicity , and its suspected carcinogenic potential, because it remains radioactive for an exceedingly long time with a half-life of approximately 4.5 billion years; and because it is also toxic in a manner similar to lead and other heavy metals. The primary radiological hazards associated with this material are alpha emissions, however the long half-life indicates that depleted uranium is only weakly radioactive. All isotopes and compounds of uranium are toxic. Such issues are of concern to civilians and troops operating in a theatre where DU is used, and to people who will live for several years afterward in such areas or breathing air or drinking water from these areas.

Studies showing detrimental health effects have shown the following:

• Indications that DU passes into humans more easily than previously thought after battlefield use. (radioactive particles absorbed into the body are far more harmful than a similar background radiation level outside the body, due to their immediate proximity to delicate structures such as DNA, bone marrow and the like.) Pre-1993 military DU studies mainly evaluated external exposure only.
• DU can disperse into the air and water, United Nations Environment Programme (UNEP) study says in part:

"The most important concern is the potential for future groundwater contamination by corroding penetrators (ammunition tips made out of DU). The munition tips recovered by the UNEP team had already decreased in mass by 10-15% in this way. This rapid corrosion speed underlines the importance of monitoring the water quality at the DU sites on an annual basis."

Because DU is a chemical toxicant heavy metal with nephrotoxic (kidney-damaging), teratogenic (birth defect-causing), and potentially carcinogenic properties, there is a connection between uranium exposure and a variety of illnesses. The chemical toxicological hazard posed by uranium dwarfs its radiological hazard because it is only weakly radioactive. In 2002, A.C. Miller, et al., of the U.S. Armed Forces Radiobiology Research Institute, found that the chemical generation of hydroxyl radicals by depleted uranium in vitro exceeds radiolytic generation by one million-fold. Hydroxyl radicals damage DNA and other cellular structures, leading to cancer, immune system damage in white blood cells, birth defects in gonocytes (testes), and other serious health problems. (See Halliwell and Gutteridge, eds. (1999) Free Radicals in Biology and Medicine, 3rd ed., Oxford University Press.) In 2005, uranium metalworkers at a Bethlehem plant near Buffalo, New York, exposed to frequent occupational uranium inhalation risks, were found to have the same patterns of symptoms and illness as Gulf War Syndrome victims,.

A report written by an Irish petro-chemical engineer stated that in Iraq, the death rate per 1000 Iraqi children under 5 years of age increased from 2.3 in 1989 to 16.6 in 1993, and cases of lymphoblastic leukaemia more than quadrupled. (K. Rirchard (1998) Does Iraq's depleted uranium pose a health risk? The Lancet, Volume 351, Number 9103). I. Al-Sadoon, et al., writing in the Medical Journal of Basrah University, report a similar increase (see Table 1 here). However, Dr. Richard Guthrie, an expert in chemical warfare at Sussex University, has argued that a more likely cause for the increase in birth defects was the Iraqi Army’s use of teratogenic mustard agents. Since more recent epidemiological findings have come to light, only the plaintifs in a long-running class action lawsuit continue to assert that sulphur mustards might be responsible. According to their CDC toxicological profile, for sulphur mustards to have produced as many birth defects as have been observed, they would have had to have also produced several dozen times as many cancers as observed. (See Gulf War syndrome for more details specifically on the controversy over the use of depleted uranium in the Persian Gulf War.)

Several sources have attributed the increase in the rate of birth defects in the children of Gulf War veterans and in Iraqis to depleted uranium inhalation exposure,. A 2001 study of 15,000 February 1991 U.S. Gulf War combat veterans and 15,000 control veterans found that the Gulf War veterans were 1.8 (fathers) to 2.8 (mothers) times more likely to have children with birth defects. In a study of U.K. troops, "Overall, the risk of any malformation among pregnancies reported by men was 50% higher in Gulf War Veterans (GWV) compared with Non-GWVs". After repeated requests, the Naval Health Research Center has refused to release the trend information from the Birth and Infant Health Registry concerning these elevated levels of birth defects. Birth defects recorded among Iraqi civilians, and U.S. and U.K. troops show similar accelerating patterns.

Early studies of depleted uranium aerosol exposure assumed that uranium combustion product particles would quickly settle out of the air and thus could not affect populations more than a few kilometers from target areas, and that such particles, if inhaled, would remain undissolved in the lung for a great length of time and thus could be detected in urine, but those studies ignored uranium trioxide gas -- also known as uranyl oxide gas, or UO₃(g) -- which is formed during uranium combustion (R.J. Ackermann, et al., "Free Energies of Formation of Gaseous Uranium, Molybdenum, and Tungsten Trioxides," Journal of Physical Chemistry, vol. 64 (1960) pp. 350-355, "gaseous monomeric uranium trioxide is the principal species produced by the reaction of U₃O₈ with oxygen." U₃O₈ being the dominant aerosol combustion product .) Uranyl ion contamination has been found on and around depleted uranium targets . UO₃ particles lead to uranyl ion accumulation in tissues including gonocytes (testes ) and white blood cells , but virtually no residual presence in urine other than what might be present from coincident particulate exposure.

By contrast, other studies have shown that DU ammunition has no measurable detrimental health effects, either in the short or long term. The International Atomic Energy Agency reported in 2003 that, "based on credible scientific evidence, there is no proven link between DU exposure and increases in human cancers or other significant health or environmental impacts," although "Like other heavy metals, DU is potentially poisonous. In sufficient amounts, if DU is ingested or inhaled it can be harmful because of its chemical toxicity. High concentration could cause kidney damage."

In October, 1992, an El Al Boeing 747-F cargo aircraft crashed in a suburb of Amsterdam. After reports of local residents and rescue workers complaining of heath issues related to the release of depleted uranium used as counterbalance in the plane, authorities began an epidemiological study in 2000 of those believed to be effected by the accident. The study concluded that because exposure levels were so low, it was highly improbable that exposure to depleted uranium was the cause of the reported health complaints.

The primary health impact of depleted uranium relates to its chemical toxicity as a heavy metal rather than to its radioactivity, which is relatively low. In fact, there is some evidence to suggest that low-level radiation, such as that from uranium, is beneficial to human beings. As with any heavy metal, the overall hazard depends on the amount of exposure.

The symptoms of Gulf War Syndrome can be explained by uranium combustion product inhalation exposure. Until the extent of uranyl oxide gas vapor production is known, the amount of uranium in exposure victims bodies will only be measurable through invasive techniques. Metallic uranium(0) shrapnel exposure and uranium(IV) oxide exposure is qualitativly and toxicologically different than hexavalent uranium(VI) uranyl compound exposure.

A two year study headed by Al Marshall of Lockheed Martin-funded Sandia National Laboratories analyzed some health effects associated with accidental exposure to depleted uranium during the 1991 Gulf War, but did not consider any nonradiological reproductive toxicity, developmental toxicity, or immuniological effects. Marshall’s study concluded that the reports of serious health risks from DU exposure are not supported by veteran medical statistics and were consistent with earlier studies form Los Alamos and the New England Journal of Medicine .

The U.S. has admitted that there have been over 100 "friendly fire" DU victims, and an unknown number of inhalation exposure victims. Uranium combustion product inhalation exposure can result in substantial harm. No formal comparison can be made between the tactical advantages and the strategic drawbacks until the congenital malformation incident rate trend is known.

Further evidence against the role of DU used in combat in causing human illness comes from another war zone. If DU caused health problems in the Gulf War zone, it would be expected to do so in other warzones, but this has not proven true in early studies. In the Balkans, "independent investigations by the World Health Organization, European Commission, European Parliament, United Nations Environment Programme, United Kingdom Royal Society, and the Health Council of the Netherlands have all have discounted any association between depleted uranium and leukemia or other medical problems among Balkans veterans."

Karyotyping measures exposure

Exposure to teratogens may be measured by karyotype tests such as those most often provided for biopsy and amniocentesis. Soluble and most partially-soluble uranyl compounds affect gonadal chromosomes in proportion to the extent that they affect white blood cell chromosomes. Uranyl poisoning causes immune system disorders and may cause cancer.

Because of the several-year delay in observed increases of teratogenisis, information about prognosis is currently uncertain. Trend information is not favorable to the afflicted, but may level out or decrease. The probability of decrease is similar to the probability of superexponential growth.

Many have recommended that the use of incendiary uranium munitions be avoided.

Urine isotope ratio tests

Some have suggested that uranyl compound exposure may be reliably classified with isotope ratios. However, the different isotopes translocate at different rates. The more-soluble uranyl compounds accumulate in cellular nuclei, where they are unlikely to return to the bloodstream or urine. Chromosomal karyotyping is the correct diagnosis procedure.

Nuclear energy applications

In a nuclear reactor, uranium-238 can be used to breed plutonium, which itself can be used in a nuclear weapon or as a reactor fuel source. In fact, in a typical nuclear reactor, up to a third of the generated power does come from the fission of Plutonium-239 (not supplied as a fuel to the reactor, but transmuted from Uranium-238).

Breeder reactors

Depleted uranium is not usable directly as nuclear fuel. Depleted uranium can be used as a source material for creating the element plutonium. Breeder reactors carry out such a process of transmutation to convert "fertile" isotopes such as U-238 into fissile plutonium. It has been estimated that there is anywhere from 10,000 to five billion years worth of Uranium-238 for use in these power plants . Breeder technology has been used in several reactors .

As of December 2005, the only breeder reactor producing power is BN-600 in Beloyarsk, Russia. The electricity output of BN-600 is 600 megawatts. Russia has planned to build another unit, BN-800, at Beloyarsk nuclear power plant. Also, Japan's Monju breeder reactor is planned for restart, having been shut down since 1995, and both China and India have announced intentions to build breeder reactors.

The Clean And Environmentally Safe Advanced Reactor (CAESAR), a nuclear reactor concept that would use steam as a moderator to control delayed neutrons, will potentially be able to burn DU fuel rods once the reactor is started with LEU. This design is still in the early stages of development.

Radiation shielding

DU is also used as a radiation shield — its alpha radiation is easily stopped by the non-radioactive casing of the shielding and the uranium's high atomic weight and high number of electrons is highly effective in absorbing gamma radiation and x-rays. However, DU is not as effective as ordinary water for stopping fast neutrons. Both metallic depleted uranium and depleted uranium dioxide are being used as materials for radiation shielding. Depleted uranium is about five times better as a gamma ray shield than lead, so a shield with the same effectivity can be packed into a thinner layer.

DUCRETE, a concrete made with uranium dioxide aggregate instead of gravel, is being investigated as a material for Dry cask storage systems to store radioactive waste.

Downblending

The opposite of enriching is downblending. Surplus highly enriched uranium can be downblended with depleted uranium to turn it into low enriched uranium and thus suitable for use in commercial nuclear fuel.

Depleted uranium is also used (with recycled plutonium) from weapons stockpiles for making mixed oxide fuel (MOX) which is now being redirected to become reactor fuel. This dilution, also called downblending, means that any nation or group that acquired the finished fuel would have to repeat the (very expensive and complex) enrichment and separation processes before assembling a weapon.

Military applications

Staballoys are metal alloys of a high proportion of depleted uranium with other metals, usually titanium or molybdenum, designed for use in kinetic energy penetrator armor-piercing munitions. They are about twice as dense as lead. One formulation has a composition of 99.25% by weight of depleted uranium and 0.75% by weight of titanium. Other variant can have 3.5% by weight of titanium.

Incendiary projectile munitions

Depleted uranium is very dense; at 19050 kg/m³, it is 70% denser than lead. Thus a given weight of it has a smaller diameter than an equivalent lead projectile, with less aerodynamic drag and deeper penetration due to a higher pressure at point of impact. DU projectile ordnance is often incendiary because of its pyrophoric property. DU munitions, in the form of ordnance, tank, and naval artillery rounds, are deployed by the armed forces of the United States, United Kingdom, Israel, France, China, Russia, Pakistan, and others. DU munitions are manufactured in 18 countries.

Most military use of depleted uranium has been as 30 mm and smaller ordnance, primarily the 30mm PGU-14/B armour-piercing incendiary round from AH-64 Apache helicopters and the GAU-8 Avenger cannon of the A-10 Thunderbolt II by the U.S. Army and Air Force. 25 mm DU rounds have been used in the M242 gun mounted on the U.S. Army's Bradley Fighting Vehicle and LAV-AT. The U.S. Marine Corps uses DU in the 25 mm PGU-20 round fired by the GAU-12 Equalizer cannon of the AV-8B Harrier, and also in the 20 mm M197 gun mounted on AH-1 helicopter gunships.

Another use of DU is in kinetic energy penetrators anti-armor role. Kinetic energy penetrator rounds consist of a long, relatively thin penetrator surrounded by discarding sabot. Two materials lend themselves to penetrator construction: tungsten and depleted uranium, the latter in designated alloys known as staballoys. The US Army uses DU in an alloy with around 3.5% titanium. Staballoys, along with lower raw material costs, have the advantage of being easy to melt and cast into shape; a difficult and expensive process for tungsten. Depleted uranium is favoured for the penetrator because it is self-sharpening and pyrophoric. On impact with a hard target, such as an armoured vehicle, the nose of the rod fractures in such a way that it remains sharp. The impact and subsequent release of heat energy causes it to disintegrate to dust and combust when it reaches air because of its pyrophoric properties (compare to ferrocerium). After a disintegrated DU penetrator reaches the interior of an armored vehicle, it explodes, often igniting ammunition and fuel, burning the crew, and causing the vehicle to explode. DU is used by the U.S. Army in 120 mm or 105 mm cannons employed on the M1 Abrams and M60A3 tanks. The Russian military has used DU munitions in tank main gun ammunition since the late 1970s, mostly for the 115 mm guns in the T-62 tank and the 125 mm guns in the T-64, T-72, T-80, and T-90 tanks.

The DU content in various munitions is 180 g in 20 mm projectiles, 200 g in 25 mm ones, 280g in 30 mm, 3.5 kg in 105 mm, and 4.5 kg in 120 mm penetrators. It is used in the form of Staballoy, alloyed with small proportion of other metals. The US Navy used DU in its 20 mm Phalanx CIWS guns, but switched in the late 1990s to armor-piercing tungsten for this application, because of the fire risk associated with stray pyrophoric rounds. DU was used during the mid-1990s in the U.S. to make 9mm and similar caliber armor piercing bullets, grenades, cluster bombs, and mines, but those applications have been discontinued, according to Alliant Techsystems. Whether or not other nations still make such use of DU is difficult to determine.

Incendiary uranium munitions may be implicated in some aspects of Gulf War syndrome and adverse reproductive outcomes such as congenital malformations. The United Nations Human Rights Commission passed a resolution to ban the use of depleted uranium in projectile weapons because they claimed it is not limited in time or space to the legal field of battle, or to military targets; it continues to act after the war; it is inhumane because it causes serious health issues, it causes harm to future civilian occupants and passers by (including unborn children and those breathing the air or drinking water); and it has an unduly negative and long term effect on the natural environment and food chain.

History

DU started to be stored in stockpiles in the 1940's when the U.S. and USSR began their nuclear weapons and nuclear power programs. While it is quite possible to design civilian power reactors with unenriched fuel, both nuclear weapons production and submarine reactors require the concentrated isotope. Originally it was conserved in hopes that more efficient enrichment techniques would allow further extraction of the fissile isotope; however those did not materialize. The Pentagon reported in the 1970s that the Soviet military had developed armor plating for Warsaw Pact tanks that NATO ammunition couldn't penetrate, and began searching for material to make harder bullets after testing various metals, ordnance researchers settled on depleted uranium.

What caused this particular material to be utilized as a form of ammunition was not only its unique physical properties and effectiveness in that role, but the fact that it was readily available, whereas tungsten, the only other candidate, had to be sourced from China. With DU stockpiles estimated to be in excess of 500,000 tons, the financial burdens associated with the housing of this kind of material quickly became apparent and that too made it more economical to use rather than store. Thus from the late 1970s onwards the US, the Soviet Union, Britain and France, began converting otherwise useless stockpiles of DU into Kinetic energy penetrators.

Photographic evidence of destroyed equipment suggests that DU was first used during the 1973 Arab-Israeli war. Various written reports cite information that was obtained as a consequence of that use.

The US and NATO Armed Forces argue that DU causes negligible increases in radioactivity and therefore minimum health risk; however, this neglects the non-radiological hazards of its toxicity. Mounting concerns have prompted calls for a ban on the use of this material, but thus far military analysts judge that its benefits outweigh its costs.

Dirty DU

There are two basic types of DU, called "clean" and "dirty". The "clean" variety is obtained as a by-product of the extraction of uranium-235 from ore in the production of nuclear fuel or nuclear weapons. "Dirty" DU is what is left over when spent reactor fuel has been reprocessed. This means it may be contaminated with far more dangerous radioactive isotopes such as plutonium.

It had been widely assumed until 2001 that the type used by the US in its weapons was the "clean" variety. But research by UN scientists found evidence of "dirty" DU in the field. The next day, the U.S. Army admitted the problem, and began to correct the issue.

Legal status

The International Court of Justice (ICJ) in their 1996 advisory opinion on the "legality of the threat or use of nuclear weapons" made it clear that under international law on poisonous weapon in paragraph 54, 55 and 56 that:

54. In this regard, the argument has been advanced that nuclear weapons should be treated in the same way as poisoned weapons. In that case, they would be prohibited under:

(a) the Second Hague Declaration of 29 July 1899, which prohibits "the use of projectiles the object of which is the diffusion of asphyxiating or deleterious gases";

(b) Article 23 (a) of the Regulations respecting the laws and customs of war on land annexed to the Hague Convention IV of 18 October 1907, whereby "it is especially forbidden: ...to employ poison or poisoned weapons"; and

(c) the Geneva Protocol of 17 June 1925 which prohibits "the use in war of asphyxiating, poisonous or other gases, and of all analogous liquids, materials or devices".

55. The Court will observe that the Regulations annexed to the Hague Convention IV do not define what is to be understood by "poison or poisoned weapons" and that different interpretations exist on the issue. Nor does the 1925 Protocol specify the meaning to be given to the term "analogous materials or devices". The terms have been understood, in the practice of States, in their ordinary sense as covering weapons whose prime, or even exclusive, effect is to poison or asphyxiate. This practice is clear, and the parties to those instruments have not treated them as referring to nuclear weapons.

56. In view of this, it does not seem to the Court that the use of nuclear weapons can be regarded as specifically prohibited on the basis of the above-mentioned provisions of the Second Hague Declaration of 1899, the Regulations annexed to the Hague Convention IV of 1907 or the 1925 Protocol (see paragraph 54 above).

This ICJ opinion was about nuclear weapons, but the sentence "The terms have been understood, in the practice of States, in their ordinary sense as covering weapons whose prime, or even exclusive, effect is to poison or asphyxiate." also removes depleted uranium weaponry from the terms of these treaties as their primary use is not to poison or asphyxiate but to destroy materiel and kill soldiers through kinetic energy.

In 1996 and 1997, the Sub-Commission on Prevention of Discrimination and Protection of Minorities of the United Nations Human Rights Commission, passed two motions the first in 1996 which:

... 1. Urge all States to be guided in their national policies by the need to curb the production and the spread of weapons of mass destruction or with indiscriminate effect, in particular nuclear weapons, chemical weapons, fuel-air bombs, napalm, cluster bombs, biological weaponry and weaponry containing depleted uranium; 2. Requests the Secretary-General: (a) To collect information from Governments, the competent United Nations bodies and agencies and non-governmental organizations on the use of nuclear weapons, chemical weapons, fuel-air bombs, napalm, cluster bombs, biological weaponry and weaponry containing depleted uranium, on their consequential and cumulative effects, and on the danger they represent to life, physical security and other human rights (b) To submit a report on the information gathered to the Sub-Commission at its forty-ninth session, together with any recommendations and views which he may have received on effective ways and means of eliminating such weapons; ...

and a second motion in 1997 which:

... 1. Urge all States to be guided in their national policies by the need to curb the testing, the production and the spread of weapons of mass destruction, or with indiscriminate effect, or of a nature to cause superfluous injury or unnecessary suffering; 2. Decide to authorize Ms. Clemencia Forero Ucros to prepare, without financial implications, a working paper, in the context of human rights and humanitarian norms, assessing the utility, scope and structure of a study on weapons of mass destruction or with indiscriminate effect, or of a nature to cause superfluous injury or unnecessary suffering.

The requested UN working paper was delivered in 2002 not by Forero Ucros but by Y.K.J. Yeung Sik Yuen in accordance with Sub-Commission on Promotion and Protection of Human Rights resolution 2001/36. He argues that the use of DU in weapons, along with the other weapons mentioned by the Sub‑Commission, may breach one or more of the following treaties: The Universal Declaration of Human Rights; the Charter of the United Nations; the Genocide Convention; the United Nations Convention Against Torture; the Geneva Conventions including Protocol I; the Convention on Conventional Weapons of 1980; and the Chemical Weapons Convention. Yeung Sik Yuen writes in Paragraph 133 under the title "Legal compliance of weapons containing DU as a new weapon":

Annex II to the Convention on the Physical Protection of Nuclear Material 1980 (which became operative on 8 February 1997) classifies DU as a category II nuclear material. Storage and transport rules are set down for that category which indicates that DU is considered sufficiently “hot” and dangerous to warrant these protections. But since weapons containing DU are relatively new weapons no treaty exists yet to regulate, limit or prohibit its use. The legality or illegality of DU weapons must therefore be tested by recourse to the general rules governing the use of weapons under humanitarian and human rights law which have already been analysed in Part I of this paper, and more particularly at paragraph 35 which states that parties to Protocol I to the Geneva Conventions of 1949 have an obligation to ascertain that new weapons do not violate the laws and customs of war or any other international law. As mentioned, the ICJ considers this rule binding customary humanitarian law. (Emphasis added).

In 2001, Carla del Ponte, the chief prosecutor for the International Criminal Tribunal for the Former Yugoslavia, has said that NATO's use of depleted uranium in former Yugoslavia could be investigated as a possible war crime.

In a paper titled "Environmental Crimes in Military Actions and the Internal Criminal Court (ICC)" written by Joe Sills et al of the American Council for the UN University, for the U.S Army Environmental Policy Institute and published in April 2002 "examine a range of perceptions within the UN Secretariat, selected UN Missions and relevant academic and non-governmental organizations (NGO) communities about the possibilities of environmental damage during military action becoming a criminal liability for military personnel and/or their contractors in the impending International Criminal Court (ICC)." They point out that The Rome Statute has one paragraph that refers to environmental damage as a war crime: Article 8(2)(b)(iv): "Intentionally launching an attack in the knowledge that such attack will cause ... long-term and severe damage to the natural environment which would be clearly excessive in relation to the concrete and direct overall military advantage anticipated." In relation to Carla Del Ponte's comments the reports states:

Considerable attention was given by the media to the decision by Carla Del Ponte, the Prosecutor of the International Criminal Tribunal on Yugoslavia, not to investigate further allegations that NATO had committed war crimes during its air campaign in Kosovo in 1999. ...

According to an interviewee close to the work of the Tribunal, Louise Arbour, Ms. Del Ponte’s predecessor as Prosecutor, was approached by six “international law types” who tried to persuade her that the NATO bombing had violated international humanitarian law; one of their allegations was that there had been crimes against the environment. The Former Republic of Yugoslavia (Serbia) had charged that the NATO bombing had constituted “environmental terrorism.” Ms. Arbour created a small, internal committee, made up of staff lawyers, to assess these allegations. Their findings were accepted and endorsed by Ms. Del Ponte, who succeeded Ms. Arbour.

While this procedure fell short of a formal investigation by the Prosecutor, the committee concluded that there had been no substantive violation of international law, and no “relevant” environmental damage (i.e., in violation of Protocol 2).

According to an interviewee, use of depleted uranium shells was a specific concern of the assessment. (Depleted uranium is extremely dense and thus increases penetration of the target. Upon impact, they can pulverize into a possibly toxic, slightly radioactive dust.)

While concern over the use of depleted uranium in Kosovo is certain to be raised again, an interviewee noted that while the use of these shells may be deplorable, in the eyes of some, it is not a war crime or a violation of international law to use , as far as the ad hoc tribunals were concerned. For either of the two tribunals to have jurisdiction, their usage would have to be banned by the Geneva Convention, which is not the case. The "Report of the World Health Organization Depleted Uranium Mission to Kosovo, 22 to 31 January 2001," does not give evidence that the alleged egregious impacts occurred; it does explain that DU poses heavy-metal toxic hazards and weak radiation hazards. DU is not described as an indiscriminately dangerous weapon that would meet the standards of danger and criminality ascribed to chemical and biological weapons. (Emphasis added)

Armor plate

Because of its high density, depleted uranium can also be used in tank armor, sandwiched between sheets of steel armor plate. For instance, some late-production M1A1HA and M1A2 Abrams tanks built after 1998 have DU reinforcement as part of its armor plating in the front of the hull and the front of the turret and there is a program to upgrade the rest.

Nuclear weapons

Most modern nuclear weapons utilize depleted uranium as a "tamper" material (see Nuclear weapon design). A tamper which surrounds a fissile core works to reflect neutrons and add inertia to the compression of the plutonium charge. As such, it increases the efficiency of the weapon and reduces the amount of critical mass required.

In thermonuclear weapons using a Teller-Ulam design (by which the energy of a fission bomb is used to start a fusion reaction), a depleted uranium "tamper" is also used around the fusion fuel. In the process of detonation, the high flux of very energetic neutrons from the resulting fusion reaction causes the U-238 tamper to fission and adds energy to the yield of the weapon. Such weapons are referred to as fission-fusion-fission weapons after the three consecutive stages of the explosion. The larger portion of the total explosive yield in this design comes from the final fission stage fueled by DU, producing enormous amounts of radioactive fission products. For example, 77% of the 10.4 megaton yield of the Ivy Mike thermonuclear test in 1952 came from fast fission of the DU tamper. Because DU has no critical mass, it can be added to thermonuclear bombs in almost unlimited quantity. The 1961 Soviet test of Tsar Bomba produced "only" 50 megatons (still the largest man-made explosion in history), over 90% from fusion, because the DU final stage was replaced with lead. Had DU been used, the yield could have been as much as 100 megatons, and would have produced fallout equivalent to one third of the global total at that time.

Civilian applications

Civilian applications for depleted uranium are fairly limited and are typically unrelated to its radioactive properties. It primarily finds application as ballast because of its high density. Such applications include sailboat keels, as counterweights and sinker bars in oil drills, gyroscope rotors, and in other places where there is a need to place a weight that occupies as little space as possible. Other relatively minor consumer product uses have included: the manufacture of pigments and glazes; incorporation into dental porcelain used for false teeth to simulate the fluorescence of natural teeth; and in uranium-bearing reagents used in chemistry laboratories.

U.S. Nuclear Regulatory Commission regulations at 10 CFR 40.25 establish mandatory licensing for the use of depleted uranium contained in industrial products or devices for mass-volume applications. Other jurisdictions have similar regulations.

Aircraft

Aircraft may also contain depleted uranium trim weights (a Boeing 747 may contain 400 to 1,500 kg). However there is some controversy about its use in this application because of concern about the uranium entering the environment should the aircraft crash, since the metal can oxidise to a fine powder in a fire. However the other hazardous material releases from a burning commercial aircraft overshadow the contributions made by DU. Nevertheless, its use has been phased out in many newer aircraft, for example both Boeing and McDonnell-Douglas discontinued using DU counterweights in the 1980s.

Forklifts

It has been stated by forklift industry leaders that the mere substitution of depleted uranium metal for iron counterweights would revolutionize the industry by ushering in design concepts not previously available. Notably reduction in overall length when applied to the crucial right-angle stacking (the amount of space required to execute a 90° turn) dimension of the forklift, results in a 10% increase in usable warehouse floor space.

Catalysts

Uranium oxides are known to have high efficiency and long-term stability when used to destroy volatile organic compounds (VOCs) when compared with some of the commercial catalysts, such as precious metals, TiO₂, and Co₃O₄ catalysts. Much research is being done in this area, DU being favoured for the uranium component due to its low radioactivity. (Hutchings, G. J., et. al., AUranium-Oxide-Based Catalysts for the Destruction of Volatile Chloro-Organic compounds,@ Nature, 384, pp. 341B343, 1996.)

Semiconductors

Some uranium oxides, namely uranium dioxide, have semiconductor properties similar to other semiconductor materials. Its band gap lies at around 1.3 eV. Its Seebeck coefficient is very high, making it a promising material for thermoelectric applications. It is also capable of withstanding high temperatures.

The low level of alpha radiation produced in the material is a cause of electronic noise, causing multiple single-event upsets. Schottky diodes made of uranium oxide and a p-n-p transistor of uranium dioxide were successfully demonstrated in a laboratory.

Pigments

Uranium was widely used as a coloring matter for porcelain and glass in the 19th century. The total production of uranium pigments was about 260 tonnes (with an uranium contents of ~70%), 150 tonnes of which were used for uranium glass. The practice was believed to be a matter of history, however in 1999 concentrations of 10% depleted uranium were found in "jaune no.17" a yellow enamel powder that was being produced in France by Cristallerie de Saint-Paul, a manufacturer of enamel pigments. The depleted uranium used in the powder was sold by Cogéma's Pierrelatte facility. Cogema has since confirmed that it has made a decision to stop the sale of depleted uranium to producers of enamel and glass.

In popular culture

The popular punk rock band Anti-Flag released a song entitled "Depleted Uranium is a War Crime" on their 2006 album For Blood and Empire.

In the video game Fallout Tactics DU rounds are a powerful item.

See also

• Gulf War syndrome

Accidental teratogens:

• Uranium trioxide (gas is aerial combustion product)
• Agent Orange
• Thalidomide

Footnotes

1. legality of the threat or use of nuclear weapons
2. Citizen Inspectors Foiled in Search for DU Weapons
3. Depleted Uranium UN Resolutions
4. Sub-Commission resolution 1996/16
5. Sub-Commission resolution 1997/36
6. E/CN.4/Sub.2/2002/38 Human rights and weapons of mass destruction, or with indiscriminate effect, or of a nature to cause superfluous injury or unnecessary suffering (backup) "In its decision 2001/36 of 16 August 2001, the Sub‑Commission, recalling its resolutions 1997/36 and 1997/37 of 28 August 1997, authorized Mr. Y.K.J. Yeung Sik Yuen to prepare, without financial implications, in the context of human rights and humanitarian norms, the working paper originally assigned to Ms. Forero Ucros."
7. The Associated Press & Reuters contributed to this report: Use of DU weapons could be war crime CNN January 14, 2001
8. Joe Sills et al Environmental Crimes in Military Actions and the Internal Criminal Court (ICC) (PDF) of American Council for the UN University, April 2002
9. The Final Report to the Prosecutor by the Committee Established to Review the NATO Bombing Campaign Against the Federal Republic of Yugoslavia: Use of Depleted Uranium Projectiles
10. Draft text (28 January 2001) of the Report of the World Health Organization Depleted Uranium Mission to Kosovo (pdf) Undertaken at the request of the Special Representative of the Secretary-General and Head of the United Nations Interim Administration Mission in Kosovo (UNMIK) 22 to 31January 2001

External links

Scientific bodies

• Canadian Uranium Medical Research Centre
• German World Uranium Weapons Conference
• U.K. Depleted Uranium Oversight Board

United Nations

• "Depleted Uranium: Sources, Exposure and Health Effects," World Health Organization, Ionizing Radiation Unit, 2001 (see Chapter 8, "The Chemical Toxicity of Uranium," in particular.)
• Sub-Commission resolution 1996/16
  (resolves and states DU to be "incompatible" with human rights and international law; lists DU as "particularly" one "weapon of mass destruction or indiscriminate effect")
• UN High Commission for Human Rights, 1998
  (statement that DU is prohibited and contravenes prior UN resolutions)
• "Human rights and weapons of mass destruction, or with indiscriminate effect, or of a nature to cause superfluous injury or unnecessary suffering"
  (The UN 2002 report)

Scientific reports

• U.S. Center for Disease Control's Toxicological Profile for Uranium (includes discussion of teratogenic and immunotoxic effects)
• Salbu, B. et al. (2005) "Oxidation states of uranium in depleted uranium particles from Kuwait," Journal of Environmental Radioactivity, 78, 125–135. Abstract: "Environmental or health impact assessments for ... DU munitions should ... take into account the presence of respiratory UO₃...."
• Wilson, W.B. (1961) "High-Pressure High-Temperature Investigation of the Uranium-Oxygen System," Journal Of Inorganic and Nuclear Chemistry, 19, 212-222, p. 213.
• Arfsten, D.P. et al. (2001) "A review of the effects of uranium and depleted uranium exposure on reproduction and fetal development," Toxicology and Industrial Health, vol. 17, pp. 180-91. Summary contains: "A number of studies have shown that natural uranium is a reproductive toxicant...."
• Hindin, R. et al. (2005) "Teratogenicity of depleted uranium aerosols: A review from an epidemiological perspective," Environmental Health, vol. 4, pp. 17. "Conclusion: In aggregate the human epidemiological evidence is consistent with increased risk of birth defects in offspring of persons exposed to DU."
• Domingo, J.L. (2001) "Reproductive and developmental toxicity of natural and depleted uranium: a review" Reproductive Toxicology, 15, 603-609.
• Durakovic A. (1999) "Medical effects of internal contamination with uranium," Croatian Medical Journal, vol. 40, pp. 49-66. Abstract: "well documented evidence of reproductive and developmental toxicity...."
• Briner, W. and J. Murray (2005) "Effects of short-term and long-term depleted uranium exposure on open-field behavior and brain lipid oxidation in rats," Neurotoxicology and Teratology, vol. 27, pp. 135-44. Abstract: "DU is a toxin that crosses the blood-brain barrier, producing behavioral changes in male rats and lipid oxidation regardless of gender in as little as 2 weeks...."
• Monleau, M. et al. (2005) "Bioaccumulation and behavioural effects of depleted uranium in rats exposed to repeated inhalations," Neuroscience Letters, vol. 390, pp. 31-6. Abstract: "depleted uranium is able to enter the brain after exposure to repeated inhalation, producing behavioral changes."
• Lestaevel, P. et al. (2005) "The brain is a target organ after acute exposure to depleted uranium" Toxicology, 212, 219-226.
• Busby, C. and S. Morgan (2006) "Did the use of Uranium weapons in Gulf War 2 result in contamination of Europe?" European Biology and Bioelectromagnetics, 1(5), 650-668.
• Depleted Uranium article from the Royal Society (does not include discussion of teratogenic and immunotoxic effects)
• An Analysis of Uranium Dispersal and Health Effects Using a Gulf War Case Study by Sandia National Laboratories (does not include discussion of teratogenic and immunotoxic effects)
• Depleted Uranium Human Health Fact Sheet by Argonne National Laboratory Environmental Assessment Division (does not include discussion of nonradiological teratogenic, developmental toxicity, and immunotoxic effects)
• Uranium Human Health Fact Sheet (does not include discussion of teratogenic and immunotoxic effects)

Other publications

• "After the Dust Settles" (Bulletin of the Atomic Scientists report from 1999)
• Better World Links on Depleted Uranium Weapons 500+ links
• 'Blowin' in the Wind' information about a film about depleted uranium by David Bradbury
• Campaign Against Depleted Uranium
• Depleted UF6 Management Information Network – on U.S. Department of Energy's inventory of depleted uranium hexafluoride.
• Guardian Unlimited's Special Report on Depleted Uranium
• International Atomic Energy Agency Depleted Uranium FAQ
• International Coalition to Ban Uranium Weapons
• My Life Living With Depleted Uranium
• Proposal for Research on Depleted Uranium (U.K. Ministry of Defence)
• Radioactive Wounds of War
• U.S. Soldiers Contaminated With Depleted Uranium Speak Out – Democracy Now!, April 5, 2004
• Uranium and Weapons – Uranium Medical Research Centre
• Annotated bibliography for depleted uranium from the Alsos Digital Library
• Nuclear Files.org information and articles relating to depleted uranium
• Have DU Will Travel series of sixteen articles in the Crawford, Texas Lone Star Iconoclast
• DU-Watch
• International Atomic Energy Agency Depleted uranium FAQ
• The Depleted UF6 Management Information Network
• Cost-Effectiveness of Utilizing Surplus Depleted Uranium (DU)

• Uranium
• Nuclear materials
• Ammunition
• Metallurgy
• Armor
• Weapons
• Gulf War Syndrome
• Neurotoxins
• Teratogens
• Immunotoxins