WASHINGTON — Countless federal records are being lost to posterity because federal employees, grappling with a staggering growth in electronic records, do not regularly preserve the documents they create on government computers, send by e-mail and post on the Web.

Federal agencies have rushed to embrace the Internet and new information technology, but their record-keeping efforts lag far behind. Moreover, federal investigators have found widespread violations of federal record-keeping requirements.

Many federal officials admit to a haphazard approach to preserving e-mail and other electronic records of their work. Indeed, many say they are unsure what materials they are supposed to preserve.

This confusion is causing alarm among historians, archivists, librarians, Congressional investigators and watchdog groups that want to trace the decision-making process and hold federal officials accountable. With the imminent change in administrations, the concern about lost records has become more acute.

“We expect to see the wholesale disappearance of materials on federal agency Web sites,” said Mary Alice Baish, the Washington representative of the American Association of Law Libraries, whose members are heavy users of government records. “When new officials take office, they have new programs and policies, and they want to make a fresh start.”