Montana officials are notifying 1.3 million people that their personal information could have been accessed by hackers who broke into a state health department computer server.
The letters are going to people whose information and records were on the server. Officials said Tuesday there is no evidence any information was stolen.
Montana Chief Information Officer Ron Baldwin says malware was discovered on the Department of Public Health and Human Services server on May 22.
The server contained names, addresses, birthdates, Social Security numbers, medical records and birth and death certificate information.
Officials say security has been updated and they are offering free credit monitoring and identity-fraud insurance.
The notifications are going to state residents, people who no longer live in Montana and the estates of those who have died.