Illinois officials say they delivered personal data involving more than 4,000 people to incorrect addresses.
A statement Friday indicated that 4,136 clients of the Departments of Human Services or Healthcare and Family Services Friday have been notified of the breach.
The personal information varied but could include names, health insurance information, medical and financial information and birth dates. Officials say there's a "very low risk" of identity theft because no detailed medical information or Social Security numbers were included.
A U.S. Postal Service change of address registry was matched to an out-of-date client file by the Department of Innovation and Technology on Feb. 9. The error was discovered March 1.
Questions may be directed to the HFS privacy officer. Credit reporting agencies and the Federal Trade Commission also have information.
