Iraq could resume poisonous chemicals manufacture even before the United Nations agrees to bar it from building offensive weapons, Mideast policy experts said.

These officials caution that production of chemicals is only a first and finite step toward the procurement of dangerous weapons. But the existence of such an industry is a critical building block in the production of chemical or biological weapons-grade material.Recent reports have suggested that massive allied bombing attacks may not have destroyed all their targets, primarily buried Iraqi storage sites.

Several days ago, the Financial Times of London reported that an Iraqi oil refinery in central Iraq was unharmed by the allied attack.

The refinery, located about 15 miles north of Baiji, produces petroleum products that are a critical component of chemical weapons, but the United States detected no significant evidence of such weapons in its war with Iraq.

"One of the troubling aspects of the war is that we're finding out that the allies destroyed less of Iraq's capability than we thought," said James Phillips, deputy director of foreign policy studies at the Heritage Foundation.

In addition to unharmed storage facility sites and the Baiji refinery, Pentagon officials acknowledged last week that they had overcalculated the number of tanks and artillery pieces destroyed by the air raids.

It remains uncertain whether Saddam still holds up to 50 pounds of weapons-grade uranium that he possessed before the war. That amount of uranium could be used in one or more atomic bombs.

Allied fighters destroyed a research reactor in January thought to contain the uranium. But officials are unsure whether the attacks destroyed the substance.

In 1981, Israel destroyed Iraq's nuclear reactor at Tuwaitha. The uranium apparently survived the attack and was moved to a different location.

Iraq has refused inspection requests by the International Atomic Energy Agency, which monitors all nuclear materials and was set to visit the country in April.

In addition to possibly owning some elements of his chemical and nuclear production capability, Saddam may possess viral cultures used to produce biological weapons. At least several cultures, typically used to develop vaccines, were provided to the Iraqis before the war by the U.S. Centers for Disease Control, Phillips said.

Still, even if Iraq has retained some aspects of its biological, chemical and nuclear elements, the fledging country is unlikely to use them for years to come, experts said.

"The real challenge here isn't making the chemicals, but delivering them," said Adam Garfinkle, a Mideast scholar at Philadelphia's Foreign Policy Research Institute.

Garfinkle noted that even before the war, Iraq apparently failed to outfit its Scud missiles with poisonous warheads.

But Garfinkle, Phillips and other experts agree that allied attacks have decimated facilities containing computers, aviation equipment and other technology needed to make weapons, particularly nuclear warheads.

The United Nations is expected to approve a cease-fire outline next week that would forbid Iraq from producing offensive weapons.

"I think we set back their nuclear program for at least a decade," Phillips said.

"We have some confidence that they can be constrained because the weapons process is technically so exotic and so hard to hide that we can have some confidence of being able to monitor it," Garfinkle said.