The Department of Energy confirmed five new cases of COVID-19 among the staff of its Washington, D.C., area headquarters, including someone who was at the office recently, in a statement posted online Friday.

The civilian agency includes the National Nuclear Security Administration (NNSA), which builds, maintains and refurbishes U.S. nuclear warheads and bombs. It has about 7,000 employees combined at the Forrestal Building in downtown D.C., and the Germantown Building in nearby suburban, Maryland, including about 1,000 NNSA employees.

Along with the bump in cases at headquarters, which makes for at least a cumulative 20 confirmed cases among the Washington-area civil service, DoE’s Savannah River Site has seen a surge in cases over the last seven days. At the site, which houses an NNSA facility where workers harvest tritium gas to recharge nuclear weapons, there were as of Friday 183 confirmed cases of COVID-19, up 52 from the week before.

The NNSA does not break out COVID-19 cases by site, but the semiautonomous nuke agency said it had, as of Friday, 129 active cases of the respiratory disease caused by the novel coronavirus across its national network of labs, manufacturing plants and sites. That was 34 more than the prior week, and upped the agency’s cumulative count of confirmed cases to 247 since the first documented U.S. case.

One of the DoE headquarters employees with a newly confirmed case was apparently working in Germantown just before receiving a positive test result, according to a statement the agency posted online last week. That set off a round of office cleaning and contact tracing, which could result in some of this person’s colleagues quarantining.

“[O]ne Germantown employee required notifications of close contacts, and areas where the individual worked are being sanitized,” DoE said.

The majority of DoE and NNSA headquarters employees have been working remotely since March, when the Department of Energy largely shut down Forrestal and Germantown. From mid-March to early June, some essential employees and top-level managers reported to the offices there occasionally. By June 8, the start of Phase 2 of DoE’s four-phase reopening plan, some 1,400 of the 7,000 DoE headquarters employees had returned to the office.

But with COVID-19 cases still climbing and schools in the Washington area poised to keep students mostly out of the classroom this fall, Secretary of Energy Dan Brouillette has said the agency will not proceed to Phase 3 of the reopening anytime soon. Phase 3 would have marked a return to essentially pre-COVID-19 operations, but the agency recently announced it would instead continue to allow people who are at greater risk of catching the disease, or who are caring for those who might be, to continue teleworking, even once headquarters transitions to Phase 3.

DoE has not set a date for transitioning to Phase 3.