The University of Maine System announced Wednesday that all students, faculty, staff and visitors be required to wear face coverings inside university buildings, regardless of vaccination status, as the delta variant surges in Maine leading into the fall semester.

The mask mandate, which takes effect immediately, will affect about 25,000 individuals who are expected to participate in face-to-face learning, work and campus life this fall on university properties.

Chancellor Dannell Malloy made the announcement in a message Wednesday to the UMaine System community. Prior to the announcement, indoor face coverings had been optional for vaccinated individuals. The announcement of a mask mandate comes two days after Bates College announced a similar requirement at its Lewiston campus.

“With our classrooms and other indoor spaces no longer set up to impose social distancing, face coverings are an important strategy we can employ to effectively control the transmission of COVID, regardless of an individual’s vaccination status and testing participation,” Malloy wrote.

The mask requirement will remain in effect at least through Sept. 30. Malloy said the university system will evaluate the state of COVID transmission and public health recommendations at the end of September and decide whether to continue the mask requirement.

He also said the requirement is somewhat flexible and may be adjusted.

“Individuals working in an office by themselves with the door closed need not wear any face covering,” he wrote. “We are considering whether we could safely and responsibly allow faculty and other instructors or presenters to temporarily remove a face covering while speaking or presenting in classrooms or presentation venues in which enhanced social distancing may be possible. And while we are not now requiring anyone to wear a face covering outdoors, doing so remains highly encouraged in large groups and especially if social distancing is impossible.

“We all want the pandemic behind us as soon as possible, but we also want to be together safely this fall,” Malloy continued. “Respecting these simply but vitally important health protocols will not only make that most likely, but also prove how important the health and well-being of our entire campus communities are to each of us.”

In addition to mandating face coverings indoors, the UMaine System is requiring all students to be vaccinated and is discussing with its labor partners the possibility of imposing vaccine mandates on all employees.

As of Tuesday, roughly 14,600 UMaine students and staff from all campuses have verified their vaccination status. That is about 42 percent of the 35,000 students and employees who make up the university population. However, of the 25,000 employees and students expected to be physically on campuses this fall, about 52 percent, or 13,307 have registered their status. The deadline to verify vaccination status is 5 p.m. Friday.

Verification will allow them to be exempt from arrival testing and quarantine requirements. Students who are not vaccinated or have only received one shot may come to campus but will have to participate in asymptomatic testing and other safety practices. Students who are not in compliance with the vaccination requirement by Oct. 15 and have not received an exemption will be asked to study remotely.

Face coverings will be required in all university buildings including the University of Maine School of Law in Portland and the University of Southern Maine campuses in Gorham and Portland, UMaine System spokesman Dan Demeritt said. Face coverings will remain optional outside university buildings, but will be strongly encouraged at large gatherings or in crowded circumstances where physical distancing is difficult to maintain.