The covered entity (CE), Wisconsin Department of Health Services, reported that a mailing error resulted in members receiving letters containing the protected health information (PHI) of individuals who no longer live at the residences. According to the breach report, the breach affected approximately 8,157 individuals. The PHI involved clinical and treatment information. The CE notified HHS, the media, and the affected individuals. In its mitigation efforts, the CE implemented new technical safeguards to prevent a reoccurrence. OCR provided technical assistance to the CE regarding the HIPAA Rules.