THE MBTA is upping enforcement of its face-mask requirement, requiring employees to confront passengers who are not wearing coverings that cover the nose and mouth.

The T previously required passengers to wear masks, using frequent on-board announcements to remind them. Enforcement, however, was based primarily on the honor system, in part because anyone claiming a medical condition was allowed to ride unmasked.

In early May, MBTA General Manager Steve Poftak said he wanted the wearing of face masks to be the norm but indicated the T wasn’t going to get heavy handed. “We won’t be refusing rides to people who are not wearing face masks,” he said at the time.

Under a new gubernatorial order that took effect Friday morning, all people over the age of 5 are required to wear face masks in areas open to the public, including public transportation. The T is directing employees to confront people not wearing masks to remind them of the order. If they refuse to comply, employees are being asked to report the situation to superiors who will then coordinate with Transit Police officers, who can issue civil fines of $300.

The governor’s order still allows people to go maskless if they claim a medical exemption. The governor’s order doesn’t require them to produce proof of their condition. Under the governor’s order, only employers and schools can demand proof from employees and students who claim a medical exemption.

Jim Evers, president of the Boston Carmen’s Union, which represents the bulk of T employees, could not immediately be reached for comment.