On May 14, 2021, On Lok Senior Health Services detected and stopped a network data security incident. The organization determined on July 6, 2021, that employee and participant information may have been compromised. Affected data included names, addresses, phone numbers, dates of birth, driver's license numbers, and health information (including immunization records and medical record numbers). Social Security numbers were exposed for employees but not for participants. On Lok engaged outside IT specialists, notified law enforcement, and offered 12 months of credit monitoring and identity theft protection services through IDX.