Nearly 9 in 10 large employers believe some of their workers will quit their jobs over the Biden administration’s coronavirus vaccine-or-test mandate, according to a survey from the Society for Human Resource Management released Monday. 

The survey reveals uneasiness among employers over the impending workplace rule, which will require employers with 100 or more employees to mandate COVID-19 vaccinations or frequent testing. They’re most concerned about losing workers amid an extremely tight labor market. 

Another two-thirds of employers surveyed said that they cannot afford to pay for weekly COVID-19 testing for unvaccinated workers. 

“Clearly, as we await the federal government’s Emergency Temporary Standard detailing how this mandate is supposed to work, employers and employees are uneasy about the potential for disruptions in the workplace,” Johnny Taylor, CEO of the HR managers’ group, said in a statement. 

Many large employers are concerned about the cost of acquiring rapid COVID-19 tests, which are growing increasingly expensive as testing requirements become more widespread. Others are worried that they could lose unvaccinated workers to rival firms with fewer than 100 employees or to independent contracting companies that aren’t subject to the rule.

While several polls have shown that large percentages of unvaccinated workers said they would quit over the vaccine-or-test mandate, real world data tells a different story. Last week, United Airlines said it would lay off around 230 employees who didn’t comply with the company’s vaccine requirement, roughly 0.3 percent of its workforce.

The Biden administration rule could go into effect soon. On Tuesday, the Occupational Safety and Health Administration submitted its draft of the vaccine-or-test mandate to the Office of Management and Budget, which will review the regulation before it goes into effect. 

Business groups generally don’t oppose the Biden administration’s effort to boost vaccinations. However, they’ve complained that they have been unable to have in-depth discussions with Labor Department officials about the specifics of the rule.

The Society for Human Resource Management surveyed 1,289 of its members online between Sept. 27-30.