The federal government mistakenly made public a 266-page report, its pages marked highly confidential, that gives detailed information about hundreds of the nations civilian nuclear sites and programs, including maps showing the precise locations of stockpiles of fuel for nuclear weapons. The publication of the document was revealed Monday in an online newsletter devoted to issues of federal secrecy. That set off a debate among nuclear experts about what dangers, if any, the disclosures posed. It also prompted a flurry of investigations in Washington into why the document had been made public. On Tuesday evening, after inquiries from NYT, the document was withdrawn from a Government Printing Office Web site. Several nuclear experts argued that any dangers from the disclosure were minimal, given that the general outlines of the most sensitive information were already known publicly. These screw-ups happen, said John M. Deutch, a former director of central intelligence and deputy secretary of defense who is now a professor at the Massachusetts Institute of Technology. Its going further than I would have gone but doesnt look like a serious breach. But David Albright, president of the Institute for Science and International Security, a private group in Washington that tracks nuclear proliferation, said information that shows where nuclear fuels are stored can provide thieves or terrorists inside information that can help them seize the material, which is why that kind of data is not given out. The information, considered confidential but not classified, was assembled for transmission later this year to the International Atomic Energy Agency as part of a process by which the United States is opening itself up to stricter inspections in hopes that foreign countries, especially Iran and others believed to be clandestinely developing nuclear arms, will do likewise. President Obama sent the document to Congress on May 5 for Congressional review and possible revision, and the Government Printing Office subsequently posted the draft declaration on its Web site. As of Tuesday evening, the reasons for that action remained a mystery. On its cover, the document attributes its publication to the House Committee on Foreign Affairs. But Lynne Weil, the committee spokeswoman, said the committee had neither published it nor had control over its publication. Gary Somerset, a spokesman for the printing office, said it had produced the document under normal operating procedures but had now removed it from its Web site pending further review. The document contains no military information about the nations stockpile of nuclear arms, or about the facilities and programs that guard such weapons. Rather, it presents what appears to be an exhaustive listing of the sites that make up the nations civilian nuclear complex, which stretches coast to coast and includes nuclear reactors and highly confidential sites at weapon laboratories. Steven Aftergood, a security expert at the Federation of American Scientists in Washington, revealed the existence of the document on Monday in Secrecy News, an electronic newsletter he publishes on the Web. Mr. Aftergood expressed bafflement at its disclosure, calling it a one-stop shop for information on U.S. nuclear programs. In his letter of transmittal to Congress, Mr. Obama characterized the information as sensitive but unclassified and said all the information that the United States gathered to comply with the advanced protocol shall be exempt from disclosure under the Freedom of Information Act. The report details the locations of hundreds of nuclear sites and activities. Each page is marked across the top Highly Confidential Safeguards Sensitive in capital letters, with the exception of pages that detailed additional information like site maps. In his transmittal letter, Mr. Obama said the cautionary language was a classification category of the International Atomic Energy Agencys inspectors. According to federal reports, a typical tube vault can hold up to 44 tons of highly enriched uranium in 200 tubes. Motion detectors and television cameras typically monitor each vault. Thomas B. Cochran, a senior scientist in the nuclear program of the Natural Resources Defense Council, a private group in Washington that tracks atomic arsenals, called the document harmless. Its a better listing than anything Ive seen of the nations civilian nuclear complex, Mr. Cochran said. But its no national-security breach. It confirms whats already out there and adds a bit more information.