Washington, D.C. ? The White House acknowledges recycling backup computer tapes of e-mail, a practice that may have wiped out many electronic messages from the early years of the Bush administration, including some pertaining to the CIA leak case.

The disclosure about recycled backup tapes came minutes before midnight Tuesday under a court-ordered deadline that forced the White House to reveal information it previously had refused to provide.

Before October 2003, the White House recycled its backup tapes “consistent with industry best practices,” according to a sworn statement by a White House aide. The White House started preserving backup tapes in October 2003, which would have been shortly after the start of the probe into who outed CIA operative Valerie Plame in July of that year.

The backup tapes, which also contain electronic documents in addition to e-mail, are the last line of defense for saving electronic records.

Separately, the White House says it is still unable to address the question of how many e-mails are missing from White House servers, or whether any are missing.

The White House “does not know if any e-mails were not properly preserved in the archiving process” from 2003 to 2005, said the statement by Theresa Payton, chief information officer for the White House Office of Administration. She said the White House continues its efforts to find out and that an assessment will be completed in the “near term.”