DES MOINES, Iowa (AP) — A Polk County public health agency that provides services for those with mental illness and intellectual or other developmental disabilities says the personal information of more than 500 patients has been compromised.

The Des Moines Register reports that Polk County Health Services admitted the mistake Friday. It says those who received services at the Crisis Observation Center in Des Moines may have been affected.

The health service says the breach occurred between June 2014 and Jan. 11. The information disclosed included names, home addresses, Social Security numbers, Medicaid identification numbers, date of admission to the crisis center and discharge location. The service says it does not have evidence the data was improperly used.

The health services offered to provide free credit monitoring for 12 months to those affected.