Former patients at the Mental Health Institute in Independence, Ia., and hundreds of state employees there and at other state facilities are being informed about a possible breach of their confidential information.

Officials said the information was stored on a backup computer tape that cannot be located. A search for the tape continues and officials said it is likely the tape was inadvertently destroyed or discarded. Access to information on the tape requires specialized and outdated equipment.

The tape does not contain any bank or credit card information, but it does include Social Security numbers and addresses for about 700 employees of several facilities managed by the Iowa Department of Human Services, which administers the facility.

The tape also includes Social Security numbers and other information regarding about 7,300 former patients at the Independence facility. A few records date back to the late 1980s but most refer to more recent patients. The tape does not include records of patients who were admitted after June 2010.

“The chance that your information was improperly accessed is small, but we realize that you may want to take steps to be sure that your information is not used by another person,” Supt. Bhasker Dave said in a statement.

In letters mailed on June 26, the department explained what happened and offered to pay for one-year enrollment in a credit monitoring service for anyone who fears that the possible breach could lead to a stolen identity.

The computer system is no longer used for patient records or employee information. Dave explained that the historical data had not been purged from the computer system and continued to be backed up on a monthly basis.