California Correctional Health Care Services (CCHCS) disclosed a data breach involving the unauthorized internal posting of employee seniority lists containing truncated Social Security Numbers (SSNs) and full names. The incident occurred between October 12 and October 24, 2022, when lists were posted on an internal nursing shared drive and a physical bulletin board at the California Health Care Facility. CCHCS discovered the error on October 24, 2022, and immediately removed the lists, replaced them with non-PII identifiers, and mandated privacy training for involved staff. No evidence of misuse was found.