State officials say a Department of State Hospitals (DSH) employee improperly accessed the health information of more than 2,000 patients, former patients, and employees at Atascadero State Hospital.
The information reportedly included COVID-19 test results.
Officials say the employee had access to the facility's data servers as part of their Information Technology job duties.
The data breach was reportedly discovered in late February as part of an annual review of employee access to data folders.
DSH officials say the employee is on administrative leave while the department investigates further, with help from the California Highway Patrol.
Officials say there is no evidence at this time that the employee used or attempted to use the information in any way.
The approximately 1,415 patients and former patients and 617 employees affected by the breach are reportedly being notified.
A Notice of Data Breach is available on the DSH website and officials say those affected who have additional questions can call DSH at (844) 227-9333.