DU weapon users argue that assessing harm, and the costly and technically challenging task of clearance, is the sole responsibility of the affected state - arguments they also used to make for land mines and cluster bombs.
Hidden in the Chilcot report: a previously classified Ministry of Defence (MoD) paper setting out the UK Government's thinking on depleted uranium (DU) munitions.
In it, the clearance of unexploded ordnance and DU is considered and the MoD argues that it has: " ... no long-term legal responsibility to clean up DU from Iraq".
Instead it proposes that surface lying fragments of DU only be removed on "an opportunity basis" - i.e. if they come across them in the course of other operations.
In other words, the UK's stance is that chemically toxic and radioactive DU 'ash' from spent munitions is strictly the problem of the country in which the munitions were used, in this case Iraq - and that the UK, which fired the DU shells, has no formal responsibility of cleaning up the mess.
The question is examined in Section 10-1 of the Chilcot inquiry which briefly considers DU in the context of the UK's obligations as an occupying power. The MoD had submitted the paper to the then newly established Ad Hoc Group on Iraq Rehabilitation.
Unlike landmines and cluster munitions, there is no treaty to ensure that affected countries receive international assistance or are themselves obligated to protect their own people. Nor is anyone required to record the impact of the weapons on individuals and communities.
Vehicles contaminated by DU - for example destroyed tanks, armoured personnel carriers - pose a particular risk to civilians, both to workers in the scrap metal industry and to children who may play on them. Levels of contamination can be high and, because the interiors are not exposed to the elements, DU may remain in the vehicles for long periods.
Just how high these levels can be was a question of scientific interest to the MoD at the time and, while tanks suspected of being struck by DU would be marked, this would be "...pending examination by an MoD-led team scientific team for research purposes." The MoD gave no guarantees that vehicles identified as contaminated would be dealt with appropriately.
DU in the UN General Assembly this October
This October, governments at the United Nations General Assembly will be debating a sixth resolution on DU weapons.
Thanks to the experiences of Iraq - who in 2014 called for assistance from the international community in dealing with contamination, and for a global ban on DU weapons - attention is increasingly being focused on this lack of obligations on nations that use DU weapons to clean up the areas they contaminate.
These same governments are often extremely conscious of the financial and technical burden of clearance as they have domestic firing ranges that are contaminated. Earlier this year, the US Army lost a long-running battle with the Nuclear Regulatory Commission over legacy DU contamination at 15 of its facilities. Meanwhile in the UK, the Scottish government continues to oppose further test firing into the Solway Firth.
The cost and complexity of dealing with DU contamination at home is not the only issue focusing minds on how governments and their militaries should be obliged to address DU following its use in conflicts. New research that has revealed the presence of DU in people 30 years after they were exposed is also showing how urine testing could identify civilians affected by the UK and US's use of DU in Iraq in 1991 and 2003.
Between 1958 and 1982, Colonie, a suburb of Albany, New York was home to National Lead Industries (NLI), a factory that manufactured products containing DU. The plant made penetrators for DU munitions, counterweights for aircraft and vehicles, and shielding for medical devices.
Lax controls on the facility meant that waste was burnt in a furnace on site, which routinely operated without filtration controls. Over the period, it is believed that more than 5,000kg of DU oxide escaped the facility in the form of micron-sized particles, to be dispersed in a plume over the surrounding community, as well as contaminating the factory itself.
For eight of those years, NLI also processed enriched uranium from fuel for experimental reactors.
Persistent US contamination akin to that in conflict zones
If the uncontrolled dispersal of DU particles into residential areas sounds familiar, it should, and the studies from Colonie have been viewed by some as analogous to the use of DU weapons in conflict settings.
Research into the shape and composition of the Colonie particles has demonstrated that they are similar to those produced by DU weapons when they hit hard targets. A UK study published in 2014 agreed that these kinds of particles are persistent in the environment, in that case surviving unaltered for 30 years in the wet conditions of a firing range in southern Scotland.
That the contamination occurred in the US itself should in theory have made the environmental and health monitoring studies that followed easier to undertake than would be the case a post-conflict setting.
However this would prove not to be the case, largely thanks to the US Agency for Toxic Substances and Disease Registry (ATSDR) - the government public health body dealing with exposures to hazardous substances. The local community would have to fight tooth and nail for recognition and research into the risks posed by the site following its closure, including collecting evidence from their friends and neighbours on the rates of health problems, which included rare cancers and immune disorders.
In 2007, and thanks to a campaign from the community that had lasted 25 years, the results of a study combining forensic environmental studies with urine analysis were published, garnering international media coverage.
The study was led by Professor Randall Parrish, then of Leicester University in the UK. All five of the former workers that they tested revealed uranium in their bodies 23 years after production had ceased, meanwhile 20% of the residents they tested were also excreting DU and, although the human sample size was small, their environmental analysis also revealed the presence of DU in homes and gardens at concentrations exceeding US intervention levels.
The publication of the results coincided with the conclusion of the main remediation programme at the NLI, which was managed by the US Army Corps of Engineers after the site was transferred to the government for a token $10. The project cost $190m, involved the removal of 150,000 tons of uranium, thorium and lead contaminated soil and debris, extracted from depths of up to 40ft, which was then sent 2,000 miles by rail to an underground radioactive waste facility in the Rockies.
Failings in the official response delayed health research
Prior to the remediation work, and Parrish and colleagues' research, an initial study by the ATSDR had already concluded that there was a real and significant health risk to the public from past DU emissions from the plant. However it had decided not to pursue any environmental surveying or health surveillance activities.
The ATSDR had been coming under pressure over the quality and independence of its work for many years and in 2009, Randall Parrish and other experts would provide evidence to a congressional committee on the ATSDR's conduct in relation to the Colonie case. In his testimony, Parrish argued that "In most respects other than providing information on toxins, [the ATSDR report] failed to deliver its remit for the Colonie site."
This April, a follow-up study on exposure rates among workers and residents was finally published. It had a larger sample size than Parrish's 2007 study, analysing the urine of 32 former workers and 99 residents. For the workers, 84% showed DU exposure, with a further 9% showing exposure to both DU and enriched uranium, whereas just 8% of the 99 residents tested were excreting DU.
One of the arguments used by the ATSDR when it had failed to act on community concerns was that too much time had passed for DU to be detected. Parrish's 2007 study was the first to show that DU was still detectable after 20 years. The latest study shows that even after 30 years it is still possible to detect the signs of DU exposure.
Just as important are the techniques they used, which can differentiate between the different isotopes of uranium, provide valuable clues to the original source of the exposure - although ascertaining how much people have been exposed to remains difficult.
Persistent particles and pernicious politics
The refusal of the ATSDR to act in the interest of the local community in the Colonie case has parallels with the behaviour of the governments who employ DU weapons in conflicts.
This is often characterised by a lack of transparency over where the weapons are fired, what they are fired at and in the quantities used. This is data that is crucial for not only determining the risk to civilians from the use of the weapons but also to facilitate the management of contamination after conflicts. It is therefore no coincidence that these themes come up time and again in United Nations' resolutions.
There has also been, and continues to be, a studied disinterest on behalf of the DU weapon users in supporting civilian exposure studies of the kind seen in Colonie. They argue that assessing harm, and the costly and technically challenging task of clearance, is the sole responsibility of the affected state - arguments they also used to make for land mines and cluster bombs.
When the United Nations last discussed DU two years ago, 150 governments recognised the need for states to provide assistance to countries like Iraq. This October, our Coalition will add our voice to those of the states affected by DU weapons in calling for an end to the use of DU weapons and for the users to finally accept responsibility for their legacy.
Colonie eventually got its exposure studies and remediation, Iraq is still waiting.
Doug Weir is the Coordinator of the International Coalition to Ban Uranium Weapons (ICBUW), which campaigns for a ban on the use of uranium in all conventional weapons and for monitoring, health care, compensation and environmental remediation for communities affected by their use. @ICBUW