UnitedHealth Group announced Tuesday that it will require COVID-19 vaccination for many U.S. employees, a move by the nation's largest health insurer that substantially broadens a push by the health care industry to get workers immunized.

UnitedHealth's requirement applies to workers who enter company facilities as well as those who meet in person with customers, members, health care providers or suppliers. It's also applicable to those who care for patients at UnitedHealth Group's growing network of medical offices, surgery centers and urgent care clinics.

A spokesman for the Minnetonka-based company said the policy applies to a "significant portion" of the roughly 220,000 employees in the U.S., including about 18,000 in Minnesota.

"UnitedHealth Group has a responsibility to do what is necessary to help ensure the health, well-being and safety of our team members and our communities," the company said Tuesday in an online statement.

Workers must be vaccinated by Nov. 30 and may request exemptions for medical or religious reasons. The company says it is making clinicians and experts available to help discuss the COVID-19 vaccine with those who are hesitant or have questions.

"Employees who do not comply, are unable to be accommodated based on their role, or do not receive an exemption, will be placed on unpaid leave, and may be terminated if they have not completed their COVID-19 vaccination series," the company said in a statement.

UnitedHealth Group is Minnesota's largest company by revenue and operates the health insurance business, UnitedHealthcare, as well as a large health care services division called Optum.

While UnitedHealth Group's policy seems to be in keeping with vaccine requirements by other national players, including CVS Health and Aetna as well as many Twin Cities area hospitals and clinics, some workers are pushing back against mandates.

In Minnesota, more than 180 health care workers spanning hospital systems across the state have asked a U.S. District Court for an injunction to stop their employers from mandating they be vaccinated from COVID-19. The say the directive violates religious freedoms and other state and federal laws.

UnitedHealth wasn't saying whether it also was motivated by President Joe Biden's executive order in September that, among other things, requires employees of federal contractors to be vaccinated by early December.

Susan Ellingstad, a partner at Lockridge Grindal Nauen in Minneapolis who specializes in workplace legal issues, speculated that UnitedHealth Group likely would fall under the federal contractor prong of the executive order. Even so, the company might have taken the step announced Tuesday, nonetheless.

"It seems like they're really taking a good approach to combining this with a lot of education and resources," Ellingstad said. "They're providing the exemptions, limited as they might be, and then even providing a sort of time before termination for people to think about it."

In addition to creating a vaccine requirement for federal contractors, Biden's executive order called on employers with more than 100 workers to require immunizations or weekly testing. The order was seen as potentially making it easier for companies in Minnesota to require vaccinations, since employers might have fewer concerns that workers in a tight labor market might simply shift to other jobs in order to avoid a vaccine mandate.

The executive order also required COVID-19 vaccinations for workers in most health care settings that receive payments from the Medicare or Medicaid government health insurance programs. By the time the order was issued, however, many Minnesota hospitals already had imposed requirements, including Minneapolis-based Allina Health System.

With more than 28,000 employees, Allina announced a mandate in August for workers across the health system's network of more than 90 clinics and 11 hospitals. Workers had until Oct. 1 to get vaccinated. As of the deadline, 88% of employees had received at least one dose of vaccine, Allina said, while 7.7% of employees had approved exemptions for religious or medical reasons.

"We have not parted ways with any employees due to vaccination status," the health system said in a statement. "Employees who are not in compliance with our COVID-19 vaccination program will be addressed in accordance with our HR policies."

Hazelden Betty Ford Foundation issued a vaccine mandate in May. By mid-August, the Center City-based addiction treatment provider reported that more than 88% of its employees, or 1,425 workers, had been vaccinated. Some 10%, or 160 employees, were exempted due to a medical or religious declination or full-time remote-work agreement.

Dr. Joseph Lee, president and chief executive of the Hazelden Betty Ford Foundation, said in a statement to the Star Tribune on Tuesday that four employees out of 1,600 were "nearing termination," and nine in 10 workers were vaccinated.