AUGUSTA, Maine (AP) — The state of Maine has begun notifying people whose personal information was included in a data breach impacting as many as 1.3 million individuals, state officials announced Thursday.

The notifications began after the state completed an assessment once they discovered that hackers exploited a vulnerability in a widely used file-transfer software. Other government agencies, major pension funds and private businesses also have been affected by a Russian ransomware gang’s so-called supply chain hack of the software MOVEit.

The specific type of data depended on the individual but could include their date of birth, driver’s license number, social security number and health and medical information.

The state said it began taking steps to patch the vulnerability, engaged with experts and legal counsel, and carried out evaluations after being alerted on May 31 of the widespread breach.

The state created a website devoted to the breach. People are encouraged to call a toll-free number to check whether their critical information was accessed. If it was then the state will provide free credit monitoring.