The covered entity (CE), Human Affairs International of California, reported that it experienced a programming issue which resulted in an employee mailing the protected health information (PHI) of 18,347 individuals to the wrong recipients. The PHI involved included names, dates of birth, addresses, diagnoses, claims and financial information, and other treatment information. The CE notified HHS, affected individuals, the media, and posted substitute notice on its website. In response to the breach, the CE provided complimentary credit monitoring services and implemented additional administrative, technical, and security safeguards. Staff were retrained on the requirements to protect and secure sensitive data.