During an appearance at the Maine Medical Center Research Institute on Friday, the Senator said repealing Obamacare is “unacceptable” because it would leave millions without insurance, the Portland Press Herald reports.

If the Senate bill were to become law, 22 million fewer Americans would have health insurance by 2026, according to a Congressional Budget Office report.

“I have deep concerns and am opposed to the Senate bill, ” she continued, adding that the bill would “make sweeping changes to the Medicaid program,” and “would take out of the Medicaid program more than $700 billion dollars.”

“You don’t take a safety net program that has been operating for more than 50 years and change it in fundamental ways without having a single hearing to evaluate its impact,” she said.

Despite opposition from some Republicans, Senate Majority Leader Mitch McConnell said this week there will be a vote to repeal Obamacare, also known as the Affordable Care Act, on Tuesday.