RIYADH, Saudi Arabia -- U.S. forces searching captured Iraqi bases and scouring the battlefield have found Iraqi warplanes, artillery pieces and huge amounts of ammunition, but also a puzzling lack of any sign of chemical weapons.
Search teams have failed to discover chemical munitions or clear evidence the munitions were ever present, according to officers at the U.S. military command, despite Iraqi President Saddam Hussein's repeated threats that his forces would use weapons of mass destruction.
Captured Iraqi soldiers have told interrogators that chemical weapons existed but invariably add that no such weapons were in their own units, an officer said. Allied soldiers also turned up no evidence that Iraq had chemical warheads for its Scud missiles.
The searches are part of the Pentagon's intensive effort to examine the effects of the latest U.S. weapons and ordnance against different types of targets, including hardened shelters, underground bunkers, artillery and advanced Soviet tanks.
After being overrun, the battlefield has become an unofficial university for a military command anxious to compare the effects of different weapons and to learn how well intelligence estimates reflected actual conditions.
Technical experts are performing their work with a sense of urgency because the opportunity to pursue it is likely to disappear soon. U.S. Gen. H. Norman Schwarzkopf, overall allied commander, has said that coalition forces would withdraw from Iraq once its government has agreed to terms for a formal cease-fire, an acceptance Iraq announced Sunday.
Of findings so far, none seems more striking than the apparent lack of chemical weapons. Allied commanders had forecast that Iraq would use poison gas against coalition forces once major ground fighting began, and they had said there was little hope air strikes could destroy all of Iraq's chemical stockpiles because not all the locations were known.
Pentagon officials had warned that Iraq could release poisons using artillery shells, short-range missiles fired from helicopters and short-range rockets mounted on trucks. There was also concern that chemical warheads had been developed for Scuds and for shorter-range Frog missiles.
The lack of those weapons remains a partial mystery, although the military command has made several attempts to solve it. Officers say Iraq either chose not to use the weapons or -- the explanation cited as more likely -- was unable to find a way to do so.
During the war, Iraq first was hampered by allied air strikes against its military industries. Some of the coalition's first targets are believed to have been a research complex for non-conventional weapons at Salman Pak and the main factory for chemical munitions at Samarra.
On Feb. 10, after more than three weeks of bombing but before the ground campaign, Defense Secretary Dick Cheney said production facilities were "for the most part, destroyed." He said air strikes had done "good work" in destroying storage facilities, but warned, "clearly he [Mr. Hussein] retains significant chemical weapons."
Undisclosed at the time were chronic production problems at the factories, U.S. officers say. Iraq had encountered difficulties removing impurities from its poison gas. The impurities limited how long chemical munitions could remain effective, making it ,, important that they be used shortly after they were filled.
Once the factories were destroyed, Iraq could not easily refill the chemical rounds in stock and could not depend on the effectiveness of the rounds once they were fired, U.S. officers say, noting that the initial air strikes clearly had caught Iraq by surprise.
"Maybe they delayed filling the munitions," an officer here said. "Maybe they didn't get enough filled in time."
Even if Iraq had managed to get chemical weapons into the field, commanders in the field may have feared how the coalition would respond if the weapons had been used. Leaflets dropped by aircraft warned officers they would be held personally responsible for firing chemical weapons and would be treated as war criminals.
Iraqi officers may also have feared for their own safety and for the safety of their troops. Few soldiers had adequate gear to protect them if clouds of poison gas had fallen onto their own positions.
Weather was another constraint. The rain and high winds could NTC have endangered Iraqi units attempting to use chemical weapons by carrying the poisons back to them.