On the battlefield, even a slight shift of wind can send poisonous clouds of chemical weapons right back onto soldiers who fire them - one reason that many of the world's nations now accept an international ban on such weapons. The US ratified the treaty in 1997.
Today, the same argument is being used by critics of depleted uranium (DU) munitions, who charge that American use of these radioactive "tank-buster" bullets in the Balkans posed as much danger to European allied soldiers as to Serb military targets.
Yesterday, the European Parliament voted to urge NATO to suspend use of the munitions, pending results of an independent study on the potential health risks. NATO last week rebuffed calls for a moratorium from Italy and Germany. Some blame the armor-piercing bullets for a string of unexplained cancer deaths and other health problems among European peacekeepers who served in Bosnia and Kosovo in the 1990s.
As the controversy rages, the issue is rekindling calls for an alternative that may better suit the needs of Western forces in post-cold war conflicts - and buries the political fallout.
At the top of the list is tungsten, another heavy metal that the Pentagon has been studying for two decades and is not radioactive. Some argue that in the future tungsten alloys - especially if propelled at speeds greater than those possible today - could match DU performance.
But for now, experts say, tungsten is costly and less effective than DU. And few American tank gunners forget that, even as Iraq yesterday marked the 10-year anniversary of the start of the 1991 Gulf War - DU was the "silver bullet" that helped destroy 4,000 Iraqi tanks with few US casualties. Iraq blames DU for a substantial increase in cancers and birth defects since the war.
Developed 'for WWIII'
"Regardless of the health risks ... [DU] has become such a political liability that [the US military] might decide to be a lot more selective in their use of it," says Chris Hellman, a senior analyst at the Center for Defense Information in Washington. "DU was developed to fight World War III, when it didn't really matter what the battlefield looked like when you got done," Mr. Hellman adds.
"When you are in a place like Bosnia or Kosovo, where civilians and your own people will be on the ground, you may decide that it's not worth using [DU]," he says. Especially "if you have a close second like tungsten."
Currently, almost the entire American arsenal of armor-piercing bullets is made of DU. A nuclear waste product, DU burns on impact, creating radioactive particles that can be dangerous if eaten or inhaled. United Nations teams have collected 340 samples from Kosovo that are being analyzed in five European laboratories, to determine possible health and environmental risks.
US military comparisons in the 1980s showed that DU was "clearly superior" to tungsten for penetrating armor, says US Army spokeswoman Nancy Ray, at the Pentagon. "We are not looking for a substitute to DU for any reason," says Ms. Ray, who adds that political considerations, so far, are not part of the equation. "In all areas, as our awareness changes, we change. We are looking for superior munitions because that is the best way to protect our soldiers," she says.
The US Navy made such an improvement in 1989, when it decided to switch from DU to tungsten bullets in its Phalanx weapons system in part "eliminating safety and environmental problems associated with DU," Navy documents show. The British Navy announced last week that it also was making the switch for its Phalanx units because US manufacturers had stopped producing DU bullets.
Focusing on toxic risks and not radioactive ones, Pentagon officials say DU exposure is no more dangerous than "old lead paint" - a view some NATO allies question. Defense department tests have shown that no cleanup treatment - except removing topsoil altogether - can turn an area contaminated with DU dust into one for "unrestricted" use.
Weighing cost, effectiveness
But is tungsten a viable alternative? Two problems, experts say, are cost and effectiveness. DU is given almost free to weapons manufacturers by the US Department of Energy, which has built up a 1.2 billion-pound stockpile since the first atomic projects of the 1940s.
By one estimate, tungsten bullets cost 10 times as much as DU, and are only 60 percent as effective. On impact with a target, tungsten forms a mushroom-shaped head, while DU self-sharpens and penetrates up to 20 percent deeper.
"[Tungsten] will never be as good as DU, we don't think," says Paul Beaver, spokesman for the London-based Jane's group, which specializes in military analysis. While tungsten can be improved with copper and titanium alloys, "we're talking about 30mm cannon shells that are going to end up the price of missiles if we're not careful."
The wider context of the DU debate may be the fact that allied casualties have been few in recent conflicts. "The problem is that a lot of people believe you can have a 'politically correct' war," Mr. Beaver adds. "People say: 'It must be safe. It must be easy.' "
Adds Hellman: "Though they didn't come to it easily, the military is becoming sensitive to collateral damage. They will never give up DU ... so they will have to come up with with a political compromise. Maybe the way is to say that, in NATO operations, we won't use this."
(c) Copyright 2001. The Christian Science Publishing Society