Iraq and Kosovo may be thousands of miles apart, but they share the dubious distinction of contamination with radioactive residue from depleted uranium (DU) bullets used in American air strikes. After several years of silence, US officials finally admitted that 340 tons of DU were fired during the Gulf war. In Kosovo, American delays in providing details of quantities and target points have frustrated international efforts to assess health risks. Despite repeated requests, NATO waited almost a full year after the start of bombing in March 1999 to say that 31,000 DU bullets -- a fraction of the number fired in Iraq -- were fired by A-10 "tankbuster" aircraft over Kosovo. A Belgrade report published this April estimates that about 50,000 DU bullets had been used in parts of Serbia and Montenegro as well as Kosovo. Evidence is plentiful on the ground that DU was used in heavily populated areas, and that civilians and returning refugees were never warned of the danger.

The high-density bullet is made of low-level radioactive waste left over from manufacturing nuclear fuel and bombs. DU bullets were designed in the 1970s to defeat top-line Soviet tanks. Some 20 nations now keep the world's best armor-piercing rounds in their arsenals. First used in combat during the Gulf war, they proved to be unmatched tank slayers. (A Pentagon official points to one other benefit: the US can give away its 1.2 billion pound stockpile of radioactive waste to weapons manufacturers.) When DU smashes into a hard target, it pulverizes into breathable dust that remains radioactive for 4.5 billion years. American nuclear scientists have found that DU dust can travel at least 26 miles. Scientists of the National Institute for Health Protection in Macedonia detected eight times higher than normal levels of alpha radiation -- the primary type emitted by DU -- in the air during the air war. Yugoslav soldiers have found DU rounds in Bujanovic in the south, and a Swiss-led international team found "serious radioactivity" when it dug up many rounds at a radio tower near Vranje.

Despite predicting that "every future battlefield will be contaminated" with DU, the Pentagon asserts that DU risk is minimal. But training materials developed in the 1990s require full protective gear and masks in contaminated areas, in line with Nuclear Regulatory Commission (NRC) rules. The US military requires an NRC license to handle the smallest amount of the restricted material. A US Army-commissioned health report issued just days before the Gulf war noted that radiation is linked with cancer and said that "no dose [of DU] is so low that the probability of effect is zero." Still, the Pentagon argues that "residual DU from battlefields in Kosovo does not pose a significant risk to human health."

US soldiers partly ascribe Gulf war syndrome to DU exposure. British troops deployed in Kosovo are suing their defense ministry for ailments they attribute to DU. The UN refugee agency in Kosovo now includes papers in personnel files to note work in potentially DU-contaminated areas. In Kosovo, Western de-mining groups were told by NATO to "exercise caution" and not to climb on destroyed armored vehicles. Last October Col. Eric Daxon, the US Army's top radiological expert, said: "The best thing I can tell anybody about entering a contaminated vehicle or damaged vehicle is: 'Don't do it. It is a dangerous place to be.'"

But that message never got through to hundreds of thousands of Kosovar Albanians, in whose name the Kosovo campaign was fought, and whose DU exposure could be highest. Rexh Himaj, a mechanic who lost most of his tools during the conflict, didn't think twice about salvaging parts from destroyed Serbian vehicles. Like thousands of returning refugees, he was just glad to get back to work.

But the concrete surface of a Serbian military base on the west side of Djakovica where I found him working was pockmarked with DU hits, as was the nearby road. The ground was littered with spent aluminum shell casings that are unique to 30 mm DU bullets. A boy climbed on a burned-out armored vehicle, then jumped off and kicked at a shell casing.

"Now I know it's dangerous, but that is a risk I've got to take," said Himaj, when the telltale casings are explained. His hands were greasy-black with work. "If [the Americans] didn't use this stuff, then we might still have Serbs here. On the other hand...I hope they clean it up." But cleanup is virtually impossible. One US Defense Department report lists eight soil decontamination techniques, including multiple nitric acid washes, but "in no case did the achieved separation suffice to allow unrestricted disposal."

A confidential preliminary UN report leaked in May 1999, as the bombing continued, did not mince words: "This type of ammunition is nuclear waste, and its use is very dangerous and harmful," it said. After NATO released its figures, the UN recommended that "measures should be taken to prevent access." For Kosovars, like Iraqis, such warnings may be too late.