An Oct. 26 article incorrectly described the size of the force searching for evidence of an Iraqi nuclear program. Of those hunting forbidden weapons in Iraq, 1 percent, not one-tenth of 1 percent, are devoted to the search for nuclear arms. The story also erred in describing the qualifications of William Domke, an employee of an Energy Department laboratory. He is an authority on Iraq's former centrifuge enrichment program, but he is not a physicist. (Published 11/01/03)

In their march to Baghdad on April 8, U.S. Marines charged past a row of eucalyptus trees that lined the boneyard of Iraq's thwarted nuclear dream. Sixty acres of warehouses behind the tree line, held under United Nations seal at Ash Shaykhili, stored machine tools, consoles and instruments from the nuclear weapons program cut short by the 1991 Persian Gulf War.

Thirty miles to the north and west, Army troops were rolling through the precincts of the Nasr munitions plant. Inside, stacked in oblong wooden crates, were thousands of high-strength aluminum tubes.

That equipment, and Iraq's effort to buy more of it overseas, were central to the Bush administration's charge that President Saddam Hussein had resumed long-dormant efforts to build a nuclear weapon. The lead combat units had more urgent priorities that day, but they were not alone in passing the stockpiles by. Participants in the subsequent hunt for illegal arms said months elapsed without a visit to Nasr and many other sites of activity that President Bush had called "a grave and gathering danger."

According to records made available to The Washington Post and interviews with arms investigators from the United States, Britain and Australia, it did not require a comprehensive survey to find the central assertions of the Bush administration's prewar nuclear case to be insubstantial or untrue. Although Hussein did not relinquish his nuclear ambitions or technical records, investigators said, it is now clear he had no active program to build a weapon, produce its key materials or obtain the technology he needed for either.

Among the closely held internal judgments of the Iraq Survey Group, overseen by David Kay as special representative of CIA Director George J. Tenet, are that Iraq's nuclear weapons scientists did no significant arms-related work after 1991, that facilities with suspicious new construction proved benign, and that equipment of potential use to a nuclear program remained under seal or in civilian industrial use.

Most notably, investigators have judged the aluminum tubes to be "innocuous," according to Australian Brig. Gen. Stephen D. Meekin, who commands the Joint Captured Enemy Materiel Exploitation Center, the largest of a half-dozen units that report to Kay. That finding is pivotal, because the Bush administration built its case on the proposition that Iraq aimed to use those tubes as centrifuge rotors to enrich uranium for the core of a nuclear warhead.

Administration officials interviewed for this report defended the integrity of the government's prewar intelligence and public statements. None agreed to be interviewed on the record. Vice President Cheney, in a televised interview last month, referred to a National Intelligence Estimate of October 2002, which said among other things that there was "compelling evidence that Saddam is reconstituting a uranium enrichment effort." Cheney said investigators searching for confirmation of those judgments "will find in fact that they are valid." His office did not respond to questions on Friday.

'Drain Pipe'

No evidence mattered more to the nuclear debate than Iraq's attempt to buy aluminum tubes overseas. Secretary of State Colin L. Powell, among many others, scorned the Baghdad government's explanation that it sought the tubes as artillery rocket casings. By August, news accounts made clear that the U.S. government's top nuclear centrifuge experts dissented strongly from the claim that the tubes were meant for uranium enrichment.

Meekin, whose remarks were supported by other investigators who said they feared the consequences of being quoted by name, is the first to describe the results of postwar analysis.

"They were rockets," said Meekin, 48, director general of scientific and technical assessment for Australia's Defence Intelligence Organisation, speaking by satellite telephone from Baghdad. "The tubes were used for rockets."

A U.S. government official, who was unwilling to be identified by name or agency, said Meekin is not qualified to make that judgment. The official did not elaborate. Kay's interim report this month said the question remains open.

Participants in the Pentagon-directed special weapons teams, interviewed repeatedly since late last spring, noted that Kay's operation has taken no steps to collect the estimated 20,000 tubes in Iraq's inventory -- some badly corroded, but others of higher quality than the ones the U.S. government intercepted in Jordan three years ago and described as dangerous technology.

"If you told me they had access to these tubes and have chosen not to seize and destroy them, it undermines the judgment that these tubes are usable for, if not intended for, centrifuge development," said Robert Gallucci, dean of Georgetown University's School of Foreign Service, who retains his classified clearances and still consults with government analysts on Iraq.

Meekin said he no longer knows the whereabouts of the tubes once stacked at Nasr. "They weren't our highest priority," he said. "The thing's innocuous." Unguarded, the tubes "could be in arms plants, scattered around, being grabbed by looters, perhaps in scrap metal yards."

Scavengers, he said, most likely have "sold them as drain pipe."

Three Fates

The day Marines and Army mechanized troops marched past the remnants of Iraq's nuclear past, Baghdad's three most important nuclear weapons scientists met three distinct fates.

Mahdi Obeidi, chief of the pre-1991 centrifuge program to enrich uranium, sat anxiously at home awaiting U.S. investigators. Jaffar Dhai Jaffar, who directed alternative enrichment efforts and other component designs under the code name Petrochemical Three, watched the U.S.-led coalition's invasion from the United Arab Emirates, to which he had decamped before fighting began. Khalid Ibrahim Said, the principal overseer of Iraq's nuclear warhead designs, drove incautiously through a newly established U.S. checkpoint. He died in a burst of gunfire from Marines.

A short and pugnacious man, unpopular among his Iraqi contemporaries, Said had been less forthcoming than the other two men in contacts with U.N. inspectors from 1991 to 1998. His loss struck a blow to U.S. occupation authorities, because there were unanswered questions about his portion of the 1991 "crash program" to build a bomb.

Said was believed to have kept comprehensive records of his work, including design details and assembly diagrams, on optical disks. Iraq delivered much of its information to inspectors in electronic form, and it did so again in its seven-volume report of Dec. 3, 2002, titled "Currently Accurate, Full and Complete Declaration of the Past Nuclear Program." That report, a copy of which has been made available to The Washington Post, was not thought to include all the technical details in Iraq's possession.

Kay said this month that Iraq took "steps to preserve some technological capability from the pre-1991 nuclear weapons program." If true, that would represent a violation of U.N. Security Council resolutions, but would fall far short of a resumption of illegal development.

"Everybody, including Donald Rumsfeld, agrees the program was destroyed 12 years ago," said one U.S. expert with long experience on Iraq. "The question for David [Kay] is whether it restarted."

Jaffar, who remains under the protection of the UAE government, agreed to voluntary interviews with U.S. and British investigators. Those familiar with his statements said he was combative, telling the Americans -- as he did during years of U.N. inspections -- that there was no hidden nuclear weapons program. Iraq, he said, never resumed the effort after U.S. bombs destroyed the Tuwaitha reactors during the Gulf War, and the International Atomic Energy Agency dismantled enrichment and design facilities over the next five years.

The Rose Garden

It was Obeidi's former program -- the use of centrifuges to enrich uranium -- that the Bush administration maintained had been resurrected. Obeidi had heard the public statements, according to two close associates, and he waited with growing anxiety for arriving troops to knock at his door.

Anxiety turned to puzzlement when they did not. After two weeks, the Iraqi scientist turned to an unlikely source of help: David Albright, a U.S. nuclear expert and cordial antagonist during Albright's years as a consultant to the IAEA. One of the first things Obeidi told Albright, by the American's account, was that he had read Albright's published writings closely in the mid-1990s to learn which of Iraq's cover stories was working.

On May 1, Albright began looking for someone in the Defense Department or U.S. Central Command who would talk to Obeidi, "but I was rebuffed." Six days later, he reached a contact in the CIA. Obeidi had important information, Albright said, and wanted to come clean.

The first meeting with the CIA, on May 17, did not go well. Obeidi wanted assurance of asylum in the United States. The interviewers were noncommittal and appeared to know little about Obeidi or the centrifuge program, according to interviews with Albright and contemporaneous notes he provided in July.

On June 2, Obeidi led investigators to his rose garden. There they dug up a cache he had buried 12 years before and kept from U.N. inspectors: about 200 blueprints of gas centrifuge components, 180 documents describing their use and samples of a few sensitive parts. The parts amounted to far less than one complete centrifuge, and nothing like the thousands required for a cascade of the spinning devices to enrich uranium, but the material showed what nearly all outside experts believed -- that Iraq had preserved its nuclear knowledge base.

The next day, U.S. Special Forces burst into Obeidi's home and arrested him -- a misunderstanding, the CIA later explained. Shortly after Obeidi's release, on June 17, the CIA made public his identity and described the rose garden cache as proof that Iraq had the secret nuclear program that the Bush administration alleged.

But that, according to sources familiar with Obeidi's account in detail, is not quite what he told his interviewers.

Joe's Return

According to close associates, Obeidi expected to speak to a peer among U.S. centrifuge physicists. He was dismayed, they said, to find that his principal interrogator lacked those credentials.

The man's name was Joe. An engineer with expertise in export controls, Joe made his reputation at the CIA as the strongest proponent of the theory that Iraq's controversial aluminum tubes were part of a resurgent centrifuge program. The CIA asked that Joe's last name be withheld to protect his safety.

In his interviews, Obeidi did not tell Joe what he wanted to hear, U.S. government officials said. Instead, Obeidi confirmed the account laid out in Volume 7 of Iraq's December nuclear disclosure, which said there had been "no nuclear activity since 1991" at seven of the program's previous sites and only "medical, agricultural and industrial" activities at the others.

The centrifuge program died in 1991, Obeidi said, and never resumed. He had buried the documents to prepare for resumption orders that never came. He had nothing to do with the aluminum tubes, he said, and a centrifuge program would have no use for them.

Obeidi's account corresponded closely with the history laid out in Volume 3 of Iraq's official history, which covered enrichment. The program began in 1988, under the designation Al Furat or 1200C, with a design based on rotors made of maraging steel. The following year Obeidi added an alternative design, using a more sophisticated rotor made of carbon fiber. In July 1990, a prototype system succeeded for the first time in separating the desired isotope of uranium from the gas uranium hexafluoride.

If Iraq had in fact revived its enrichment program, it would have needed a fluorine plant to convert uranium ore to that gaseous form and an intricate system of magnets, bearings and pipes to connect thousands of rotors in cascades. Kay's investigators, allied officials said, have found none of those things.

The physics of a centrifuge would not permit a simple substitution of aluminum tubes for the maraging steel and carbon fiber designs used by Obeidi. The tubes in Obeidi's design were also specified at 145mm in diameter; the aluminum tubes measured 81mm.

Joe sent dispatches to Washington over the summer accusing Obeidi of holding back the truth, according to a U.S. official who read one. The Iraqi scientist, fearful of his safety after being named in public, moved with his family to a CIA safe house in Kuwait. For months, he remained in limbo.

"They're just in a conflict of interest," Albright said in a July interview, speaking of Joe and other CIA analysts. "Their bosses are [still] saying the tubes are for centrifuges."

By summer's end, under unknown circumstances, Obeidi received permission to bring his family to an East Coast suburb in the United States. He declined through intermediaries to be interviewed, and a government official asked that his location not be published. Albright, who hopes to employ Obeidi at his Washington-based Institute for Science and International Security, is no longer willing to discuss the case.

Book of the Month Club

At Hussein's former palace complex in Abu Ghurayb, lush by Baghdad standards with two small artificial lakes, frustrated members of the nuclear search team by late spring began calling themselves the "book of the month club."

"There's a lot of guys over there read more novels than they will the rest of their lives," said a recently returned investigator, speaking on condition of anonymity. "You've got some bored people over there, big time."

Nuclear investigators had come with expectations set by Bush and Cheney, who gave rhetorical emphasis to Iraq's nuclear threat in their most compelling arguments for war. At least four times in the fall of 2002, the president and his advisers invoked the specter of a "mushroom cloud," and some of them, including Defense Secretary Donald H. Rumsfeld, described Iraq's nuclear ambitions as a threat to the American homeland.

On the ground in Iraq, one investigator said, the nuclear investigation began as and remained "the least significant of the missions." The resources, personnel and operational pace of the nuclear team, he said, "were minuscule compared to chem and bio," a reference to chemical and biological weapons probes.

Fewer than one-tenth of 1 percent of the search personnel had nuclear assignments, about a dozen out of 1,500 at the peak strength of the Iraq Survey Group. In the immediate postwar period, investigators had about 600 leads in an "integrated master site list," of which the U.S. Central Command identified a "Top 19 WMD," for weapons of mass destruction. Only three of those were nuclear-related: Ash Shaykhili Nuclear Facility, the Baghdad New Nuclear Design Center and the Tahadi Nuclear Establishment.

"There really wasn't a need for our specialized area of work," Navy Cmdr. David Beckett said in a recent interview. In Iraq, Beckett commanded a group of nuclear-trained Special Forces known as the Direct Support Team. Now program manager for special nuclear programs at the Defense Threat Reduction Agency, Beckett said the aluminum tubes and machine tools cited in the October 2002 National Intelligence Estimate -- vacuum tubes, industrial magnets and balancing machines -- were "not a big focus" of his work in Iraq. He added, "To be honest, I've read more about that since I got back."

An administration official, defending the CIA's prewar analysis, said its message had been widely misunderstood. "The term 'reconstituting' means restoring to a former condition, a process often inferred to be short term," he said. "Based on reporting, however, Saddam clearly viewed it as a long-term process. So did the NIE."

Fertile Ground

Meekin, the Australian general who had principal responsibility for collecting Iraqi military technology, said his 500-member unit is disbanding, its work largely done. According to U.S. government officials, some of Kay's leading nuclear investigators have already left Iraq. Nuclear physicist William Domke, who ran the centrifuge investigation, returned last month to his intelligence post at the Energy Department's Lawrence Livermore National Laboratory. Jeffrey Bedell, Domke's counterpart at the Los Alamos National Laboratory, has also come home.

Domke and Bedell, according to people who know their work, confirmed their prewar analysis that the tubes were not suited for centrifuges and that Iraq had no program to use them as such. They had seen the tubes in December and January, on temporary assignment for the IAEA in Iraq. They were also principal authors of the Energy Department's dissent from the National Intelligence Estimate of October 2002.

Neither man replied to messages left by voice mail and e-mail. Steve Wampler, a spokesman at Livermore, said, "They really don't talk about their work." A U.S. government official, speaking for the administration but declining to be named, denied that the two physicists had reached final conclusions. "Domke may be coming back soon," the official said. "Their work is not completed."

Tim McCarthy, an experienced U.N. inspector who returned to Iraq late last month to join Kay's team, said in an interview before departing that the Iraqi rocket program based on 81mm tubes had been known to Western analysts "well before 1996." McCarthy said inspectors gave the tubes "maybe three minutes out of 100 hours" of attention because they did not appear to be important.

Meekin said the Nasr 81 rocket "appeared in a public arms show in 1999" at which Iraqi munitions were displayed for sale. Such sales would have been illegal under U.N. Security Council sanctions, but hardly secret. Meekin said trade magazines covered the show.

Partly for those reasons, the American-led search teams did not even visit Nasr until July. Iraqi Brig. Gen. Shehab Haythem showed them around, the tubes laid out in neat rows. Investigators sent samples to the Sandia National Laboratories in New Mexico and left the rest.

Today, Ash Shaykhili is a hulk. What it contained, apart from demolished remnants of the 1991 program, was exactly the kind of equipment that the CIA cited as part of its compelling case for Iraq's nuclear threat: "magnets, high-speed balancing machines, and machine tools."

"They're not acting as if they take their own analysis seriously," said Joseph Cirincione, director of the nonproliferation project at the Carnegie Endowment for International Peace. "If they were so worried about these tubes, that would be the kind of sensitive equipment you'd think the administration would want to seize, to prevent it from going somewhere else -- Iran, Syria, Egypt."

The investigation to date, Meekin said, suggests that Iraqi efforts to obtain dangerous technology since 1991 met with modest success at best.

"By and large, our judgment is that sanctions have been pretty good, or the sanctions effort, to prevent the import of components," he said. In the realm of nuclear proliferation, he said, "I guess there's more fertile ground in North Korea or Iran."

Intercepted aluminum tubes in Iraq, as shown in a slide used by Secretary of State Colin L. Powell during his U.N. speech in February. "The tubes were used for rockets," says Australian Brig. Gen. Stephen D. Meekin, above, not for nuclear arms plan.