The boxes contained the names and social security numbers of the decedents but the risk of anyone's personal identification being compromised is low, officials said in a Washington Post report Friday.
The manager of the storage facility discovered the boxes when he went to clear out the unit after he was unable to collect rental payment.
Cemetery officials told the subcommittee Thursday the records were duplicates meant for digitizing and they were apparently put into the storage unit by an employee of the company hired to digitize them.
The U.S. Army's Criminal Investigative Division is looking into the incident, said Kathryn Condon, director of the Army's cemeteries program. All but one box of records were returned to cemetery officials, an Army spokesman said. He declined to say why the single box was retained.
U.S. Rep. Bill Johnson, R-Ohio, said he found it "extremely troubling that boxes containing this kind of information were left unsecured and only discovered allegedly due to a lack of payment for the use of a storage facility … I take this breach very seriously."