The personal information of more than 10,000 people who the city fire department treated may be affected after an employee's personal hard drive was lost in March, officials announced Friday.

The breach affects 10,253 people whom EMS treated from 2011 to 2018.

The department said personal information, including 3,000 social security numbers, stored on the drive may have been compromised. The agency says there is no evidence any of the information has been accessed.

FDNY officials said the affected patients were notified by mail this week.

The employee, who was not identified and was authorized to access the records, had uploaded the information onto the drive, the department said.