The Defense Department and Office of Personnel Management expect to have merged two offices and moved 2,000 federal employees and a 600,000-case backlog of security clearance investigations nine months from now.

The new office will be established under the Defense Security Service by Oct. 1, Director for Defense Intelligence Garry Reid told the House Armed Services Committee during a hearing Wednesday on the security clearance backlog. The office will absorb the National Background Investigations Bureau, established in the wake of the 2015 OPM network breach.

Originally, NBIB was created to handle the majority of background investigations while the Defense Department built out secure infrastructure to maintain those operations, called the National Background Investigations Services system. As the backlog grew—hitting a peak of 725,000 this April—Congress ordered NBIB to transfer Defense investigations to DSS. Rather than split the work between two departments, the administration plans to move all clearance work to the Defense Department.

“We were working through the process of splitting out of an enterprise, and there’s risk associated with that,” Reid said. “This is actually much more streamlined for us from an efficiency standpoint,” as the Defense Department makes up 70 percent of the clearance caseload.

Reid said DSS and NBIB have begun to strategize on how the merger will take place but have yet to start the process, pending an executive order from the president. The offices are working on details on how to best use physical resources—such as real estate, computers and office supplies—as well as human resources, including personnel and job functions.

DSS Director Dan Payne told the committee he has already begun integrating NBIB’s senior staff into his organization.

“Below the senior staff levels, I know that employees at both agencies are concerned about their jobs, their duty locations, their change in command,” Payne said. “I am committed to minimizing the disruption to both field workforces—the people on the ground doing the work and accomplishing our mission.”

Payne said he and NBIB Director Charles Phalen are working on a detailed plan for this transition but noted this is not a simple task.

“We are integrating two organizations into DSS while simultaneously automating and changing operational processes and procedures,” he said. “Everyone at this table recognizes these complexities and are resolute in ensuring it is done successfully.”