Yale New Haven Health officials said the personal information of some patients was compromised in an April data breach.
Officials said that certain demographic information such as names, addresses, phone numbers, emails, Social Security numbers, treatment locations and preferred languages were included in the Elekta databases impacted by the breach.
A small group of people may have had their financial information exposed during the breach, as well, according to officials.
Anyone with information that could have been exposed will be notified by mail and people who may have had their financial information exposed will be offered complimentary credit monitoring service.
Elekta is is a company that provides the software to run linear accelerators for radiation treatment. Since the cyberattack was contained to their system, Yale officials emphasized that the attackers never had access to the hospital system's electronic medical records.
"Yale New Haven Health truly regrets any inconvenience this has caused. As a premier healthcare provider, we strive to demonstrate respect for patients and our community and to always safeguard that information," the hospital system said in a statement.
After an investigation by Elekta, Yale New Haven Health was notified on May 26 of the access to its patients' data. Because of this, the hospital system "undertook an extensive internal investigation to determine what information was potentially exposed and which people were affected."
Yale New Haven Health is just one of nearly 40 hospitals nationwide impacted by the cyberattack. For more information about the data breach, click here.