Despite this colossal effort, Parrish and his colleagues found high concentrations of DU particles in soil, stream sediments and household dust in the vicinity of the site, deposited long ago when the factory burnt the shavings and chips produced by the weapons manufacturing process: the study estimates that, over the years, about 10 tons of uranium oxide dust wafted from the chimney into the surrounding environment.

The Army Corps clean-up team tested the soil from some of the gardens of houses backing on to the plant, and in cases where it was found to be emitting more than 35 pico curies of radiation per gram they removed it. The researchers discovered dust in and around buildings emitting up to 10 times as much. DU, inhaled in the form of tiny motes of oxide that lodge inside the lungs, emits alpha radiation, nuclei of helium. Unlike the gamma radiation produced by enriched, weapons-grade uranium, alpha particles will not penetrate the skin.

But inside the body DU travels around the bloodstream, accumulating not only in the lungs but also in other soft tissues such as the brain and bone marrow. There, each mote becomes an alpha particle hotspot, bombarding its locality and damaging cell DNA. Research has shown that DU has the potential to cause a wide range of cancers, kidney and thyroid problems, birth defects and disorders of the immune system.

When DU ‘penetrators’ - armour-piercing shells that form the standard armament of some of Britain’s and America’s most commonly deployed military aircraft and vehicles - strike their targets, 10 per cent or more of the heavy DU metal burns at high temperatures, producing oxide particles very similar to those at Colonie.

TV footage shot in Baghdad in 2003 shows children playing in the remains of tanks coated with thick, black DU oxide, while there have long been claims that the DU shells that destroyed Saddam Hussein’s tanks in the 1991 Gulf war were responsible for high rates of cancer in places such as Basra.

Parrish’s team includes David Carpenter, an environmental health expert from Albany University. ‘DU burns, it releases particulates that can be breathed in, and it doesn’t go away,’ he says. ‘The issue does not concern military personnel as much as civilian populations in theatres where they are used. Now we know that we can still find measurable levels of DU among the people of Colonie, we need a much bigger study to establish whether they have suffered disproportionate ill-effects such as cancers as a consequence. If they have, it would raise a serious ethical challenge to the use of these weapons. Arguably it could constitute a war crime.’

The NL plant on Central Avenue, Colonie’s main artery, opened in 1958 and became one of the Pentagon’s main suppliers. DU - the material left in huge quantities by the process of refining enriched uranium for bombs and nuclear reactors - is extremely dense. A pointed rod fired at high velocity will penetrate not only armour but several feet of concrete. In 1979 a whistleblower from inside the plant told the local health department that it was releasing large amounts of DU from its 50ft chimney, which was not properly filtered. The state government carried out atmospheric tests and in 1981 ordered that main production cease. The factory shut three years later.

One of those who has now tested positive is Mike Aidala, 71, who worked at the plant for 22 years and became its health and safety director. ‘When it started, the place was spotless,’ he says. ‘But over the years it got dirtier and dirtier. We burnt the chips produced by the lathes in a steel furnace.’ He added: ‘A lot of my co-workers died young. Whether the plant was the reason, I guess we’ll never know.’

As concern in Colonie rose, a residents’ group began to call for a publicly funded health study. For Anne Rabe, a founder member of a campaign that has now lasted for 25 years, the Parrish study represents overdue vindication. ‘I do find it very ironic that the US government at state and federal level refused for so long to do anything, and now the UK comes along and has funded these tests,’ Rabe says.