TAMPA, Fla. — Tampa General Hospital is informing patients that a hack to its system from a criminal group resulted in the theft of personal information of more than a million people.

The hospital is mailing letters to alert people about a recent cybersecurity event that involved some patient and team member information. As many as 1.2 million people may have been impacted.

The hospital says that unusual activity was detected on computers on May 31.

Hospital officials said they immediately took steps to contain the activity and began an investigation with the assistance of a third-party forensic firm.

However, the investigation determined that an unauthorized third party accessed TGH’s network and obtained certain files from its systems between May 12 and May 30.

The hospital reported the event to the FBI and provided information to support its investigation of the criminal group responsible.

The information varied by individual, but may have included names, addresses, phone numbers, dates of birth, Social Security numbers, health insurance information, medical record numbers, patient account numbers, dates of service and/or limited treatment information used by TGH for its business operations. 

Hospital officials said they will be mailing notification letters to individuals whose information may have been involved in this event and is also providing individuals whose Social Security number was involved with complimentary credit monitoring and identity theft protection services.