Three months later, the government still hasn't told 21.5 million employees their data was hacked

The U.S. government has not yet notified any of the 21.5 million federal employees and contractors whose security clearance data was hacked more than three months ago, officials acknowledged on Tuesday.

The agency whose data was hacked, the Office of Personnel Management (OPM), said the Defense Department will begin "later this month" to notify employees and contractors across the government that their personal information was accessed by hackers.

OPM said notifications would continue over several weeks and "will be sent directly to impacted individuals." OPM also announced that it hired a contractor to help protect the identities and credit ratings of employees whose data was hacked.