Federal health officials recently expanded their masking recommendations beyond public indoor spaces to include crowded outdoor settings in areas where COVID-19 transmission levels are high.
In Minnesota, that includes most areas of the state, including Ramsey County, home of the Minnesota State Fair.
While fair officials had already recommended face coverings in outside crowds, the new guidance underscores the increasing risk of transmission in settings that were once considered to be safer.
"This of course is yet another indication that the highly infectious delta variant is changing the game," state infectious disease director Kris Ehresmann said. "We aren't going to wish away this virus, and delta is particularly good at finding you if you let down your guard."
The outdoor masking recommendation is another response by health officials to control the delta variant, which is causing serious illness in the unvaccinated but also can infect those who are fully vaccinated, who typically develop less severe illness.
But the recommendations ask for voluntary compliance because most states have ended public health emergencies that enable mandates. Minnesota's ended in late June, just as the delta variant was taking hold.
Oregon issued an outdoor mask mandate on Tuesday, two weeks after imposing an indoor mandate. In Minnesota, private businesses can set their own mandates for employees and visitors to their buildings.
New COVID-19 cases have been traced to recent outdoor events by Minnesota health officials.