Never mind any radioactive hazards, America's tank gunners seem to agree on one thing: They are safer in battle because their firing chambers are loaded with depleted-uranium (DU) bullets.
"This is our favorite round," says Capt. Robert Kiermayr, of Phoenix, Ariz., whose armored unit faced off against Iraq during a tense period last year. "People just love to shoot it."
The armor-piercing power of this bullet, a two-foot-long dart made of radioactive waste material, became clear when it was first used in combat during the 1991 Gulf War. Nearly 4,000 Iraqi tanks and armored vehicles were destroyed.
It is the "absolute best," says Sgt. 1st Class William Poe, the 3-69th Armored Division master gunner in Kuwait last spring. "It will defeat any armor system on earth, is extremely accurate, and it saved lives during the war. Now DU is state-of-the-art." The risk, he says, "is overblown."
The US Navy may have had different thoughts. It has switched to another heavy metal, tungsten, that is only a fraction as toxic and not at all radioactive.
The Navy "quietly evaluated the downside of using DU in its Phalanx Gatling gun" and in 1989 decided to switch to tungsten, notes military analyst Bill Arkin.
"It was proven that the tungsten penetrator provides improved round effectiveness while eliminating safety and environmental problems associated with DU," says the Naval Sea Systems Command history for that year, obtained by Mr. Arkin.
Navy spokesperson Lt. (j.g.) Kimberley Marks says the primary reason for the switch was the "overwhelming performance advantages" of tungsten.
BUT while 1990 tests found that tungsten best suited the Navy's particular needs, DU won out for the other services. One big difference is that DU rounds self-sharpen as they penetrate armor, unlike tungsten rounds, which mushroom on impact.
And unlike tungsten, DU is cheap. The US nuclear industry has amassed 1.2 billion pounds of DU since the Manhattan Project of the 1940s, and it is given away almost free of charge to weaponsmakers - a big bonus for the cost-conscious military. But tungsten must be paid for, and half the US supply currently comes from China.
As early as 1978, then-Sen. Bob Dole raised questions: "They seem to have chosen this material for bullets because uranium metal is dense and because DU is cheap," he said on the Senate floor. "Needless to say, I find this proposal shocking."
DU panels are also used to reinforce armor in M1A1 tanks. They are marked with the letter "U," welded onto the front right of the turret.
Another difference is cleanup. Tungsten doesn't require any. For DU, by contrast, one Defense Department report lists eight soil decontamination techniques, but says that "in no case did the achieved separation suffice to allow unrestricted disposal."
Army documents show that six American Bradley Fighting Vehicles were buried in Saudi Arabia during the Gulf War because of "substantial non-removable DU contamination." Three captured Iraqi vehicles meant for museums "could not be placed on public display without substantial risk."
Sixteen other US vehicles were shipped to a custom-built $4 million decontamination facility at Snelling, S.C., where they were scraped, ground, and etched with acid to remove DU traces. Despite such rigorous efforts, six of those vehicles had to be buried in a low-level radioactive waste dump.
Even some veterans who have been exposed still advocate its use - as long as soldiers are taught how to protect themselves.
"For combat effectiveness, DU wins hands down," says Doug Rokke, a former Pentagon health physicist who was exposed as part of the Army's Gulf War DU assessment team." If I had to go into combat and had a choice [about using DU], I would fire it."
But during the Gulf War, few soldiers were told of DU risks, or that particles can spread uncontrollably with wind and weather. Like chemical weapons - which are now banned by international treaties, in part for this reason - DU does not know an enemy from an ally.