The  Department of Energy late Monday published the framework that its employees and support services contractors will use to plan their return to federal sites and offices during the continuing COVID-19 pandemic.

The civilian agency manages nuclear weapons design and production sites through its semi-autonomous National Nuclear Security Administration.

DoE’s framework quantifies that there are four phases in the oft-discussed federal “phased approach” to reopening: phase 0 through phase 3. Phase 0, which applies to many facilities now, means conducting only the “[m]inimum necessary onsite mission.” Phase 3 means “unrestricted staffing of DoE worksites,” according to the documents posted to the agency website.

Phase 1 involves returning mission-critical personnel to work “whose jobs can be better performed onsite than through telework,” the department said. Self-identified vulnerable federal employees will not have to return to the site during Phase 1, nor will those “who live with or provide care for individuals in the vulnerable population.” Federal employees who are caring for others and cannot find caregiving services during work hours also will not have to come back in the first phase.

Even the first phase of return to work is contingent on local and regional conditions. To begin Phase 1, a site’s host region must identify a decline in reports of flu- and COVID-19-like symptoms, and COVID-19 cases over two weeks. Regional hospitals also must have the capacity to care for “all patients without crisis care,” and healthcare workers should have access to virus- and antibody testing themselves.

Phase 2 would see more federal support staff return to the sites.

There are about 14,000 federal employees across the DoE complex, including those who do not work on defense-nuclear programs.

The management and operations contractors of major DoE sites, including National Nuclear Security Administration sites, are responsible for writing their own reopening guidelines. Those published Monday apply to DoE federal sites and on-site support services contractors who work there.

The National Nuclear Security Administration has continued work on its most critical nuclear weapons programs during the pandemic, if not always at the same pace it could have managed without the damping effect of a nation-wide response. For example, work at Los Alamos National Laboratory on a plutonium pit factory slowed down in late March and April as workers at the site’s Plutonium Facility left and then slowly returned to the desert campus. Pits are the fissile cores of nuclear weapons, responsible for starting a warhead or bomb’s nuclear chain reaction.