Under the House bill, large employers could choose the benefit requirements from any state—including those that are allowed to lower their benchmarks under a waiver, health analysts said. By choosing a waiver state, employers looking to lower their costs could impose lifetime limits and eliminate the out-of-pocket cost cap from their plans under the GOP legislation.

The measure would give employers added flexibility to take steps that could lower costs by limiting more-expensive coverage areas. And it would lessen the federal regulation of insurers, a goal of GOP lawmakers who believe the ACA is an example of government overreach.

The impact on employer plans expands the scope of the health bill to affect, potentially, everyone not insured by Medicare or small-business plans, since the bill also includes cuts to Medicaid and changes to the individual market. Employer health plans are the single largest source of health insurance in the country, with about 159 million Americans receiving coverage through their jobs.

“It’s huge,” said Andy Slavitt, former acting administrator of the Centers for Medicare and Medicaid Services under President Barack Obama. “They’re creating a backdoor way to gut employer plans, too.”