An audit prompted in part by the loss of the Wright Brothers' original patent and maps for atomic bomb missions in Japan finds some of the nation's prized historical documents are in danger of being lost for good.

Nearly 80 percent of U.S. government agencies are at risk of illegally destroying public records and the National Archives is backlogged with hefty volumes of records needing preservation care, the audit by the Government Accountability Office found.

The report by the watchdog arm of Congress, completed this month after a year's work and obtained by The Associated Press, also found many U.S. agencies do not follow proper procedures for disposing of public records....