Restaurants and bars should consider installing sneeze guards at their registers. Mass transit workers should close every other row of seats on their buses. Students should eat lunch in their classrooms instead of congregating in a cafeteria.

These are among the social distancing measures that the Centers for Disease Control and Prevention listed in a document it quietly released on its website this week outlining recommendations for reopening restaurants, mass transit, schools and childcare programs across the United States amid the coronavirus pandemic.

The detailed 60-page document was posted on the CDC’s website with no accompanying announcement from the public health agency, and comes weeks after many states have already ended or partially ended their lockdowns.

Full coverage of the coronavirus outbreak

It also comes amid reports of strife between the CDC and the Trump administration: While the White House released a plan called “Opening Up America Again” in April that incorporated some CDC suggestions, it largely left reopening decisions up to governors and local officials.

Meanwhile, the CDC’s coordinated, national approach — with more details and restrictions — had previously been shelved by Trump administration officials for being too specific, the Associated Press reported last week after obtaining parts of the CDC guidance.

Not all businesses and institutions should reopen yet, depending on the number of coronavirus cases in their local areas, the CDC cautioned. It recommended a three-phased approach for each community to take, each one more permissive than the next, provided rates of transmission do not spike.

In Step 1 of the plan for schools, for example, schools that are currently closed will remain closed. In Step 2, they will be open with “enhanced social distancing measures” and attendance will be restricted to those who live in the local area only; in Step 3, they are open with distancing measures and attendance restricted to areas with limited transmission of the coronavirus.

“While some communities will progress sequentially through the reopening phases, there is the possibility of recrudescence in some areas,” the CDC acknowledged. “Given the potential for a rebound in the number of cases or level of community transmission, a low threshold for reinstating more stringent mitigation standards will be essential.”

For all institutions, the CDC recommended thorough disinfection for high-traffic areas: door handles of businesses, turnstiles in mass transit stations, playground equipment at schools. It urged face coverings in any area where it would be impossible to socially distance, including for staff in childcare settings and for older children in schools. And it encouraged plentiful hand sanitizer in schools, as long as it was safely stored away from children, and on tabletops at restaurants.

Tener Goodwin Veenema, a professor and visiting scholar at the Johns Hopkins Center for Health Security, welcomed the federal guidance, but said she felt in some cases, the verbiage the CDC used was too weak — citing examples in the document where it called the measures “considerations.” (For restaurants and bars, the document advises, “Consider assigning workers at high risk for severe illness duties that minimize their contact with customers and other employees,” for instance.)

“When we have a pandemic of this nature, people need facts, and they need definitive action statements: ‘This is what needs to happen in the presence of an ongoing outbreak,'” Goodwin Veenema said.

That is especially important, she added, given the mixed messages that the federal government has made about reopening as politicians and public health officials tangle over stay-at-home orders aimed at stopping the spread of the disease that have sent the economy into a freefall.

The tension between agencies “has created a lot of confusion. It’s perpetuated fear, and it’s led to some ambiguous decision-making,” Goodwin Veenema said.

The White House did not immediately respond to a request for comment from NBC News on the CDC guidelines.

The document comes in the same week that all 50 states have either opened or partially reopened, despite no vaccine or cure yet for the coronavirus. As of Wednesday, there have been more than 1.5 million cases of COVID-19 in the United States, with about 93,000 deaths attributed to it.