WASHINGTON (NEXSTAR) — The Food and Drug Administration says there should be relief soon for parents who are struggling to get baby formula, but lawmakers are still demanding answers about what led the shortage to this point.

FDA Commissioner Robert Califf told a House committee Thursday that the Abbott Nutrition plant in southwestern Michigan, the largest producer of baby formula in the country, could be back up and running “in the next week to two weeks” after having been shuttered since February.

“We’ve already made significant progress,” Califf told representatives.

President Joe Biden on Wednesday said he was invoking the Defense Production Act to bolster the production of baby formula. The administration is also launching an operation to fly in formula made abroad.

“We will not let infant formula into the U.S. that is not safe,” Califf said.

While they welcomed the progress, lawmakers on both sides of the aisle expressed frustration with the FDA’s handling of the shortage.

“We need answers and we need them now,” Rep. Rosa DeLauro, D-Conn., said.

She said the FDA must explain why it took so long to respond to bacterial contamination concerns at the Abbott plant.

“How many more illnesses and deaths were caused due to the FDA’s slow response?” she wondered. “It makes me question which side the FDA is on: Are they on the side of Abbott and industry or the side of the American consumer?”

Rep. David Valadao, R-Calif., blamed the Biden administration for not taking the shortage seriously.

“This administration appears interested in alleviating the issue, but is has taken too long to get to this point,” he said.

Democrats have also blamed a lack of resources within the FDA. On Wednesday, they passed a bill to send $28 million in emergency funding to the FDA. Republicans did not support that bill, calling it too expensive.