BANGOR – Eastern Maine Medical Center says it lost track of a hard drive containing personal information of 660 patients.

The Bangor hospital announced Thursday that it’s mailing notices to patients to ensure that they take precautions to avoid identity theft.

Officials say the hard drive contained names, dates of birth, medical record numbers, one-word condition descriptors and images from a specific type of cardiac procedure performed at the hospital. The procedures took place between Jan. 3, 2011, and Dec. 11, 2017.

Police are investigating the theft.

Officials say the risk of identity theft is minimal because the hard drive didn’t contain Social Security numbers, addresses, or financial information. Nonetheless, all of those patients will be eligible for identity theft monitoring for a year.