WASHINGTON – Estimates of the number of graves that might be affected by mix-ups at Arlington National Cemetery grew from hundreds to as many as 6,600 on Thursday, as the cemetery’s former superintendent blamed his staff and a lack of resources for the scandal that forced his ouster.

John Metzler, who ran the historic military burial ground for 19 years, said he accepts “full responsibility” for the problems.

But he also suggested cemetery employees and poor technology were to blame for remains that may have been misidentified or misplaced. He said the system used to track grave sites relied mostly on a complicated paper trail vulnerable to error.

Metzler and his deputy, Thurman Higginbotham, were forced to retire after the Army inspector general’s office found that as many as 211 graves were unmarked or misidentified. The report accused Metzler of repeatedly failing to ensure burials were being done properly and of failing to respond after unmarked graves were discovered.

Sen. Claire McCaskill, chairwoman of an oversight panel on the Senate Homeland Security and Government Reform Committee, said Thursday that she believes 4,900 to 6,600 graves may be unmarked or mislabeled on maps.

Metzler said an inspector general finding that more than 100 graves lacked a headstone or burial card was not entirely accurate and that it was mostly internal working maps that were mislabeled.