A Pentagon report released Tuesday revealed for the first time that some ashes from the cremated unidentified partial remains of victims of the 9/11 attack on the Pentagon and in Shanksville, Pa., had been sent to a landfill.

The revelation was made in three brief mentions in a report released by an independent  Pentagon panel headed by retired Gen. John Abizaid.   The panel had been tasked with correcting procedures at the  Armed Forces Mortuary at Dover Air Force Base, which had been accused of "gross mismanagement."

The earlier review corroborated allegations made by whistle-blowers that in two instances very small amounts of body tissue had been lost at the facility that serves as the main arrival point for the remains of service members killed in Afghanistan and Iraq.

For much of the past decade, the mortuary at Dover has contracted a medical waste company to cremate and incinerate any small unidentified portions of bone or tissue from service members killed in Iraq and Afghanistan that might remain after the identification process has been completed.

From 2003 to 2008, the waste company disposed of any remaining ashes in a southern Virginia landfill, but that policy changed in 2009 and any remaining ashes are now disposed of at sea.  Before the policy change, the ashes of the partial remains of at least 274 service members had been disposed of in the landfill.

When the reports first surfaced in November,  Air Force officials said they only had paperwork going back to 2003 and were unclear when the practice actually began.  But the report released today found  the practice actually began a year earlier, with some of the unidentified partial remains of victims of the  Sept. 11, 2001, terrorist attack on the Pentagon.

A brief mention in the report says, "This policy began shortly after Sept. 11,2001, when several portions of remains from the Pentagon attack and the Shanksville, Pa., crash site could not be tested or identified.

"These cremated portions were then placed in sealed containers that were provided to a biomedical waste disposal contractor," the report continues.  "Per the  biomedical waste contract at that time, the contractor then transported these containers and incinerated them."

The report makes no mention of how many remains from Sept. 11 victims may have been disposed in this manner.  Presumably they could not be identified because there was no DNA matter remaining in the small charred pieces of tissue that may have remained.

Dover Mortuary officials assumed that no remains would be left, but after an inquiry they were told "that there was some residual material following incineration, and that the contractor was disposing of it in a landfill. The landfill disposition was not disclosed in the contractual disposal agreement. "

Two additional references were included in an appendix to the report, but did not mention Shanksville.  The first  mention  was to  a July 25, 2002, memo from the acting director of army casualty and mortuary, citing the disposal of "Group F" "remains from the attack on the Pentagon as nonassociable and nonbiological specimens through incineration."  The description identifies  "Group F" remains as being "nonassociable fragment remains that cannot be further identified."

The other reference in the appendix refers to an Aug. 7, 2002, note from the commander of the 436th Air Wing to his master sergeant to dispose of Group F remains.  A subsequent email "specifies incineration."

The 9/11 attack on the Pentagon killed 184 people when a hijacked airliner crashed into the building.   Another 40 passengers were killed aboard the plane that crashed into a Shanksville, Pa.,  field  after passengers struggled to take control of the airplane from hijackers.

A March 2, 2002, memo from David Chu, then serving as Under Secretary of Defense for Personnel and Readiness, authorized that "non-associable fragmented remains" of Pentagon 9/11 victims that could not be further identified or were mixed with "non-biological material" could be treated "in the same manner as any biological tissue removed for surgical or diagnostic purposes."  The sole example listed  for disposition of such remains was "by incineration."

The memo, obtained by ABC News, also requests that any remains positively identified as belonging to the terrorists be "transferred to the FBI."   It also contained instructions that any victims' remains positively identified after the initial release of remains to next of kin should be cremated together if next of kin agreed.  Twenty-five families did agree to this and an urn containing these kinds of  remains was interred in a casket at Arlington National Cemetery.

It is unclear whether the families of 9/11 victims were aware that unidentified remains had gone to contractors and then to the landfill, or if they had given previous consent, as has been the case with the families of military service members.

The families of military service members  are provided with forms on which they can sign off on the disposition of any portion of remains that could not be identified or are found after most of the remains have been turned over to families for burial.

In a statement, James Laychak, president of the Pentagon Memorial Fund, whose brother Dave died in the 9/11 attack, said his organization was aware of the report.   Although he said the  fund had not received a copy, "we are grateful for the willingness of the Department of Defense and other members of the subcommittee to conduct the independent review."

"We appreciate the department's commitment to meeting the highest standards of care for the remains of our fallen heroes," he said.