The Los Alamos National Laboratory confirmed a pair of COVID-19 cases among its workforce last week, during which the lab performed nearly 400 tests for the viral disease, a spokesperson said late Friday.

That brings the total number of confirmed cases at the lab since the start of the outbreak to 59, the spokesperson for the lab’s management and operations contractor said in an email. None of these had been fatal, at deadline. The lab had performed 5,621 COVID-19 tests, as of late last week. Los Alamos has since late May had a mandatory random testing policy for personnel reporting for work on site.

Some 5,000 of the lab’s roughly 13,000 employees were working on site last week, the Los Alamos spokesperson said. About 60% of the workforce were still off-site, at that time.

Among other facilities, the laboratory has kept the PF-4 Plutonium Facility at Technical Area 55 open and staffed for most of the pandemic. Likewise, Los Alamos permitted research, development, and manufacturing of detonators at Technical Area 22 to continue during the COVID-19 response. There has been at least one confirmed case of the disease among the PF-4 workforce. 

Usually, the lab requires anyone potentially exposed to a person with a confirmed case to self-quarantine for two weeks.