WASHINGTON —  A portable hard drive that may contain the personal information of up to 48,000 veterans may have been stolen, the Department of Veterans Affairs and a lawmaker said Friday.

An employee at the VA medical center in Birmingham, Ala. reported the external hard drive missing on Jan. 22. The drive was used to back up information on the employee's office computer. It may have contained data from research projects, the department said.

The employee also said the hard drive may have had personal information on some veterans, although portions of the data were protected. Secretary of Veterans Affairs Jim Nicholson said that the VA and the FBI are investigating.

Rep. Spencer Bachus, R-Ala., said that the personal information of up to 48,000 veterans was on the hard drive and the records of up to 20,000 of them were not encrypted.

Pending results of the investigation, VA is planning to send individual notifications and to provide a year of free credit monitoring to anyone whose information is compromised.