The Energy Department says personal information for about 14,000 past and current employees was compromised after the department's computers were hacked. Information such as Social Security numbers and names was disclosed in the attack, which occurred in late July.
The department said in a memo to employees that its cybersecurity office was working with other officials, including a health, safety and security office and the agency's inspector general, to investigate the incident. The memo said no classified data was targeted or compromised.
A department spokeswoman declined to comment.
The memo says workers whose information was compromised will be offered assistance on ways to protect themselves from identity theft.