The US government accidentally posted on the Internet a list of government and civilian nuclear facilities and their activities in the United States, but US officials said Wednesday the posting included no information that compromised national security. However, Energy Secretary Steven Chu, questioned about the disclosure at a House of Representatives hearing, expressed concern with respect to a uranium storage facility at the department's Oak Ridge Y12 facility in Tennessee. The facility holds large quantities of highly enriched uranium, which if obtained could be used to fashion a nuclear weapon. "That's of great concern," said Chu, referring to the Y-12 site. "We will be looking hard and making sure physical security of those sites (at Y12) is sufficient to prevent ecoterrorists and others getting hold of that material." Later Chu told reporters that while the disclosure may be embarrassing, "there's no secret classified information that's been compromised (and) the sites and everything are public knowledge" already available elsewhere. But, he added, the list "gathers it up" in a single document, and that is of some concern. The 266-page document was published on May 6 as a transmission from President Barack Obama to Congress. According to the document, the list was required by law and will be provided to the International Atomic Energy Agency. Some of the pages are marked "highly confidential safeguards sensitive." Energy Secretary Steven Chu, questioned about the disclosure at a House hearing, said he was concerned about the disclosure as it relates to a uranium storage facility at the Oak Ridge National Laboratory Y-12 facility in Tennessee. The facility holds large quantities of highly enriched uranium, with if obtained can be used to fashion a nuclear weapon. "That's of great concern," said Chu, referring to the Y-12 site. "We will be looking hard and making sure physical security of those sites (at Y12) is sufficient to prevent ecoterrorists and others getting hold of that material." Chu said he had no details how the document was released, beyond that it involved the government printing office. "Someone made a mistake," said Chu, appearing before a House Appropriations subcommittee. Damien LaVera, a spokesman for the National Nuclear Security Administration, said the document had been reviewed by a number of US agencies and that disclosure of the information did not jeopardize national security. He said the document is part of an agreement on nuclear material inspection under the IAEA's nuclear nonproliferation effort. "While we would have preferred it not be released, the Departments of Energy, Defense, and Commerce and the NRC all thoroughly reviewed it to ensure that no information of direct national security significance would be compromised," LaVera said in a statement. An Energy Department official, who spoke on condition of anonymity because the official was not authorized to discuss the situation publicly, said none of the sites on the list are directly part of the government's nuclear weapons infrastructure. In addition to the Y12 facility, the document includes some facilities at the Energy Department's Hanford nuclear site in Washington state and various civilian nuclear fuel processing sites including uranium enrichment facilities, according to government officials. Uranium stored at the Y-12 site is scheduled to be moved into a new $549 million high-security warehouse in 2010, said Y-12 spokesman Steve Wyatt. The 300-by-475-foot (91-by-430 meter), fortresslike warehouse, under construction since 2004, will replace several aging vault-like storage facilities. Included in the report, however, are details on a storage facility for highly enriched uranium at the Y-12 complex at the Oak Ridge National Laboratory in Tennessee and some sites at the Energy Department's Hanford nuclear site in Washington state, this official acknowledged. Beth Hayden, a spokeswoman for the Nuclear Regulatory Commission, said the agency reviewed the document as it relates to civilian facilities with NRC licenses and "we are confident that information of direct national security significance was not compromised." The NRC has jurisdiction over commercial nuclear power plants and civilian uranium processing and storage facilities. The publication of the list was first reported in an online secrecy newsletter Monday. The document had been posted on the Government Printing Office Web site, but has since been removed from that site. In a statement, the Government Printing Office said Wednesday: "Upon being informed about potential sensitive nature of the attachment in this document, the Public Printer of the United States removed it from GPO's Web site pending further review. After consulting with the White House and Congress, it was determined that the document, including sensitive attachment, should be permanently removed from the Web site." The GPO said it processes and produces approximately 160 House documents during the two-year congressional cycle, and the list was received by the agency in the normal process and produced under routine operating procedures. The document includes both government and civilian nuclear facilities, all of which have various levels of security, including details and location of nation's 103 commercial nuclear power reactors, information readily available from various sources. The document details the location of the nuclear sites and what is being done there. For instance, there are nuclear reactors at the Westinghouse Electric Company in Pittsburgh, Pa. This facility is currently working on research into what happens when there are accidents with the nuclear reactors. The project started in 2006 and is expected to end in 2012, according to the document. There are "zero" national security implications to the publication of this document, said Steven Aftergood, director of the Federation of American Scientists' Project on Government Secrecy. Aftergood found the document on the GPO Web site and highlighted it in his online bulletin. "I regret that some people are painting it as a roadmap for terrorists because that's not what it is," Aftergood said. "This is not a disclosure of sensitive nuclear technologies or of facility security procedures. It is simply a listing of the numerous nuclear research sites and the programs that are under way," Aftergood said. "And so it poses no security threat whatsoever."