Students returning to school this fall must wear face masks, the state clarified Friday in a new public health order, adding that face shields aren’t as effective in stopping the spread of coronavirus.

The order said that every person on school property, including on busses, must wear a mask that covers their nose and mouth. These covering most not have see-thru openings, be secure under the chin and fit snugly against the sides of one’s face and nose.

“Recent studies are showing that not all face coverings provide equal protection against COVID-19,” said Gov. Gary R. Herbert in a statement. “As we send our children back to school, we need to make sure that they are wearing face masks that actually reduce the spread of coronavirus in the air.”

That was the first of two moves Friday to redefine how the state plans to manage coronavirus outbreaks.

Herbert also issued an executive order that changes the terminology around its color-coded response to the coronavirus.

Instead of referring to the colors as “risk levels,” the order renames them “levels of restriction.”

The terminology refocuses colors on what they actual mean — the amount of restrictions in place, not the perceived risk people have of catching the virus.

Herbert said in early July that the state had erred when it created that system.

He said, “We identified by the four-color coding, of red, then orange, then yellow, then green — we identified them by risk. I think that’s given us misinformation. … What people thought when they heard ‘yellow’ is, ‘Ah, low risk.’ We’ve probably dropped our guard a bit, and gotten a little complacent.”

The order also states that a political subdivision can adopt mask mandates without getting approval from the Utah Department of Health.

The order came after the state’s public health and economic recovery committee decided on Friday that data shows Salt Lake City could move from the orange, moderate restriction level to the less-restrictive yellow.

But SLC Mayor Erin Mendenhall says she won’t make the move just yet.

“While Salt Lake City data is showing improvement, known hot spots continue to be elevated and the recommendation from public health experts continues to be keeping Salt Lake City in the orange phase until there are additional data improvements,” Mendenhall said in a statement provided to The Salt Lake Tribune.

Since a high point in early July, case counts are trending downward in SLC, Salt Lake County Health Department data shows. As of Thursday, the county reported SLC had seen just under 4,000 known coronavirus cases since the outbreak began. There are 337 current cases.

Salt Lake City is the lone part of the state currently in the orange level. The rest of the state is either in the yellow or green restriction level.

Sen. Dan Hemmert, co-chairman of the Public Health and Economic Emergency Commission, said that the commission supports Mendenhall if she wanted to move the city to the yellow restriction level.

Hemmert, R-Orem, said the commission had seen data that indicates SLC could make the transition safely. While the commission isn’t urging Mendenhall to make the move, Hemmert said he, personally, was.

“My personal opinion is, yeah, she should move to yellow,” Hemmert said. “And I think the data suggests she could. But I recognize she’s the mayor of Salt Lake City. I’m not, and she’s going to make the decision she thinks is best.”

The state reported 552 new COVID-19 diagnoses on Friday, a number they say is “artificially high” because it includes results from 144 delayed tests.

For tests processed during the past seven days, Utah has averaged 369 new positive results per day, according to the Utah Department of Health. Gov. Gary Herbert had said he wanted the state to have fewer than 400 new cases per day by Sept. 1 — and after three weeks of declining numbers, it would take a sharp rise in infections to surpass that.