As the coronavirus pandemic continues to spread across the country, one of the underlying problems that has emerged in the federal government’s bungled response has been the potential costs associated with seeking COVID-19 testing. As Rep. Katie Porter (D-Calif.) explained during a House oversight committee hearing on Thursday, an uninsured person who goes to an emergency room for testing could face bills adding up to well over $1,000. If that person needs to be put in isolation, the cost could be far more. “Fear of these costs are going to keep people from being tested, from getting the care they need, and from keeping their community safe,” she said.

But, as Porter discovered, there’s a little-known federal regulation that gives the Centers for Disease Control and Prevention director the power to use government funds to cover the costs for “care and treatment of individuals subject to medical examination, quarantine, isolation, and conditional release” during a health crisis. And during Thursday’s hearing, she appeared to convince the CDC’s director, Dr. Robert Redfield, to agree to use that authority pay for COVID-19 testing to be provided “free to every American regardless of insurance.”

I just got goosebumps. @RepKatiePorter just obliterated CDC Director Robert Redfield in her questioning about the coronavirus. pic.twitter.com/AlYBXPFdrZ — Mother Jones (@MotherJones) March 12, 2020

After pulling out her trademark whiteboard to calculate the potentially astronomical costs for an uninsured person to be tested for COVID-19, Porter grilled Redfield on the existing rules. Redfield hesitated at first, saying only that he would “review it in detail” with CDC and Department of Health and Human Services officials. Porter wasn’t satisfied with that response and noted that she and two of her colleagues—Rep. Rosa DeLauro (D-Conn.) and Rep. Lauren Underwood (D-Ill.)—had first raised the issue in a letter to Trump administration officials last week. “You need to make to make a commitment to the American people so they come in to get tested,” she said. “You can operationalize the payment structure tomorrow.”

With that, Redfield seemed to have a change of heart. “I think you’re an excellent questioner,” he said, “so my answer is yes.”

Porter is already promising to hold the administration to this commitment. “Dr. Redfield was under oath when he testified that he would make coronavirus testing free, and the American people rightly expect that witnesses appearing before Congress are wholly truthful,” Porter said in a statement provided to Mother Jones. “I expect Dr. Redfield to follow through on his commitment, and you can bet I’ll hold him to account if he doesn’t.”