Two more people at the Department of Energy’s Forrestal Building headquarters in Washington, D.C., have tested positive for COVID-19, Secretary of Energy Dan Brouillette said Friday.

One employee has not been in the buildng since March 13, the other since March 27, Brouillette said in the statement. Both have since recovered in self-quarantine, he added.

The civilian DoE maintains and modernizes U.S. nuclear weapons and nuclear weapons production infrastructure.

That raises the total number of confirmed positive cases at agency headquarters to at least 10, according to statements DoE has posted online since March 18. Of the confirmed headquarters cases, four people have recovered and one person has died, according to official tallies from Brouillette’s office.

In the Friday statement, DoE said it followed its usual procedure of notifying personnel who may have had contact with the infected individuals, and deep-cleaned the area where they usually work.

Two weeks ago, DoE confirmed the first case of COVID-19 at the agency’s Germantown, Md., building. That is the only positive case the department has acknowledged at Germantown.

Some senior DoE managers are still occasionally reporting to work at the Forrestal Building, while the majority of perosnnel telework.

Meanwhile, the federal government last week began general preparations for returning the civil service to work after months of teleworking that may yet continue.