Tri-City (California) Medical Center’s chief executive says the hospital has sent letters of intent to fire five employees, and has disciplined a sixth, for allegedly posting information about hospital patients online.

The health care district did not specify what kind of patient information was posted to the online site, reported to be Facebook, but hospital CEO Larry Anderson said in a statement that it did not involve patient names, photographs or “similar identifying information.”

Anderson also didn’t specify who was fired, but the North County Times has reported that the five terminated employees were nurses. A call to the California Nurses Association was not immediately returned.

An investigation is ongoing, according to Tri-City, which says it will take further disciplinary action to prevent similar incidents in the future.

The Health Insurance Portability and Accountability Act forbids health care workers from obtaining or sharing “personally identifiable” information about patients. It specifically protects patients’ names, medical record numbers and health status, among other identifiable information.

In May 2007, Tri-City fired 10 employees for taking cell phone pictures of at least one patient’s X-ray without permission.