At least 15 people were involved and there were 23 "violations" and seven "infractions" issued as part of the department's ongoing investigation.
The State Department has been investigating Clinton's email from the time she was Secretary of State during the Barack Obama administration. She deleted some 30,000 emails and scrubbed hard drives after she left the post, and subsequent probes have found that she mishandled classified material.
No names of Clinton staffers were released. In a letter to Sen. Charles Grassley, the Republican chairman of the Senate Finance Committee, the department said it "does not release the names of current or former employees participating in the security incident program."
"However, in the spirit of cooperation, the Department can share with you certain information about the status of the ongoing review. To this point, the Department has assessed culpability to 15 individuals, some of whom were culpable in multiple security incidents. DS has issued 23 violations and 7 infractions incidents under 12 FAM 550. This number will likely change as the review progresses."