Army Secretary John McHugh announced Thursday that the cemetery's two civilian leaders would be forced to step aside, and he appointed a new chief to conduct a more thorough investigation to examine the graves and sort out the mix-up.
"I deeply apologize to the families of the honored fallen resting in that hallowed ground who may now question the care afforded to their loved ones," McHugh told a Pentagon news conference.
Arlington National Cemetery is considered among the nation's most hallowed burial sites, with more than 300,000 people buried there with military honors. An average of 30 funerals are conducted there every day.
Among those buried at the cemetery are troops killed in Iraq and Afghanistan, as well service members from past conflicts dating back to the Civil War.
Famous presidents and their spouses, including members of the Kennedy family, also have been buried there. The cemetery, located across the Potomac River from Washington in northern Virginia, attracts more than 4 million visitors annually.
An Army investigation was launched last year after reports of employee misconduct, first reported by the Web site Salon.com.
Led by the service's inspector general, Lt. Gen. Steven Whitcomb, the investigation found lax management of the cemetery, where employees relied on paper records to manage the dozens of burials each week and maintain the thousands of existing gravesites.
Whitcomb said at least 211 remains were identified as potentially mislabeled or misplaced and that there could be more.
"We found nothing that was intentional, criminal intent or intended sloppiness that caused this. ... But of all the things in the world, we see this as a zero defect operation," he told reporters Thursday.
Whitcomb could not say how old the mixed-up remains might be or from what conflict, saying only that the problem had been confined to three areas of the cemetery known as sections 59, 65 and 66.
Whitcomb said he did find two cases of mis-marked graves in section 60, the area for veterans from Iraq and Afghanistan. He said those mistakes had been corrected.
Dorothy Nolte, 68, of Burns, Tenn., said she learned last year that the remains of her sister, Air Force Master Sgt. Marion Grabe, who had been buried at Arlington in March 2008, had been moved to a new grave site. Nolte said she went to Arlington to find out that her sister's urn had been buried on top of another soldier, but then it was disinterred and moved to another grave site. She said she had not been informed of the transfer.
"I made them unearth the urn so I could see the name," Nolte said in a phone interview Thursday from New York. "I have peace knowing my sister is indeed in the right place."
As for the Army investigation, "I think that it's a good thing that the truth is coming out, and it's certainly a situation that needs to be rectified," she said.
Separately, the Army is investigating whether the cemetery's deputy superintendent, Thurman Higginbotham, made false statements to service investigators. Higginbotham, who ran the day-to-day operations at the cemetery, has been accused by former employees of creating a hostile work environment and breaking into their e-mail systems.
Higginbotham is on administrative leave, pending further review.
According to a defense official familiar with the case, who discussed the details on condition of anonymity, Higginbotham won't face criminal charges because of a lack of evidence. But, the official said, the Army will ensure he never works at the cemetery again.
The official wasn't authorized to speak publicly about the case because it is ongoing.
Higgenbotham's boss, John Metzler, is set to retire on July 2. Service officials say he is being pushed out with a letter of reprimand that blames him for failing to rein in Higginbotham's mistakes.
Taking their place will be Kathryn Condon, a former civilian head of Army Materiel Command who as executive director will in charge of fixing any burial errors. Patrick Hallinan, a director with the Veterans Affairs Department, is temporarily being assigned as the cemetery's superintendent.
McHugh also announced the creation of an independent advisory commission that will be led by former senators and Army veterans Max Cleland and Bob Dole.
Family members with questions are urged to call the cemetery at 703-607-8000.