The California Department of Social Services has reported a possible large-scale breach of personal data for some 700,000 home care workers and patients.

The possible breach was discovered when a payroll mailing for California In-Home Supportive Services providers arrived damaged and with some information missing.

The package contained names and Social Security numbers for hundreds of thousands of providers and recipients of home care in the state, the department says on an FAQ page about the event.

The department states it currently has "no reason to believe" that any of the compromised data have been used for fraudulent purposes and promises to implement more stringent security measures to prevent a similar event in the future.

The FAQs are posted here.