Going to a Pennsylvania business that remains open during the pandemic? Be prepared to wear a mask. That goes for workers, too.

Many commercial buildings that serve the public will be required to make sure customers wear masks — and deny entry to anyone who refuses — under an order signed Wednesday by the state health secretary. The policy went into effect Sunday at 8 p.m.

Employees will also have to wear face coverings, including those who work in warehouses, manufacturing facilities and other places that remain in business but aren’t open to the public.

The mask mandate was included in a wide-ranging order that will govern many aspects of how a business operates — from how it arranges its break room to how many patrons it can allow inside at any one time — as the administration of Democratic Gov. Tom Wolf confronts a pandemic that has killed at least 1,225 in Pennsylvania and sickened thousands more.

Wolf said the latest order is meant to protect supermarket cashiers, power plant operators and other critical workers who can't stay home and are at heightened risk of contracting the virus.

“Our essential workers have stepped up to the plate and are keeping us safe, healthy, fed and sheltered during this time, and we all need to thank them (by) doing everything we can to prevent ourselves from spreading the virus to them,” he said at a video news conference.

Wolf is ratcheting up pressure on retailers, warehouses and other establishments to enforce social distancing guidelines and minimize the spread of the new coronavirus just as majority Republicans in the state Legislature seek to ease his administration’s shutdown of businesses it doesn’t consider “life sustaining.”

Wolf previously closed schools and nonessential businesses and ordered people to stay home.