The head of the Food and Drug Administration will testify before Congress for the first time Thursday about the baby formula shortage, which has alarmed American parents and has become a growing political liability for President Joe Biden.

The appearance of FDA Commissioner Robert Califf before a House subcommittee comes just hours after Biden announced a more aggressive response to the issue, including invoking the Defense Production Act to expedite domestic manufacturing and authorizing flights to import formula from overseas.

Califf is the first administration official to testify before Congress on the issue, which has left some parents searching for a solution and has become a political talking point for Republicans. Several factors are contributing to the shortage, including supply disruptions caused by the coronavirus pandemic and the recent closure of the largest US formula factory.

The FDA announced several steps to address the issue earlier this week, including a preliminary agreement with formula maker Abbott Nutrition to reopen its plant, which has been closed since February due to contamination. In addition, the agency is making it easier for international manufacturers to import more formula.

Members of a House Appropriations subcommittee have indicated that they will question Califf about why the FDA did not act sooner to help alleviate supply issues. Lawmakers have also claimed that the FDA failed to detect problems at Abbott’s plant as early as last fall.

Rep. Rosa DeLauro, D-Conn., recently filed a whistleblower complaint alleging numerous safety violations at Abbott’s plant, including employees falsifying records and failing to test formula properly before releasing it. According to her, the former Abbott employee notified the FDA of the situation in October but was not interviewed by agency personnel until late December.

There are also concerns about the FDA’s timeline for dealing with Abbott. After FDA inspectors began investigating four bacterial infections in infants who had consumed formula from the plant, the company closed its Michigan plant in February. The first of these cases was reported to the FDA in September, but inspections of the facility did not begin until late January. Califf stated earlier this week that the agency’s investigation is ongoing and that no conclusion has been reached on whether bacteria from the plant caused the infant infections. Abbott claims there is no direct link between its products and the illnesses.

The baby formula shortage is Califf’s first major crisis since rejoining the FDA in February. He briefly led the agency under President Barack Obama and was rehired based on his previous experience leading the sprawling agency that regulates food, drugs, medical technology, and tobacco.

While the baby formula shortage will undoubtedly take center stage, the FDA’s budget request for next year was originally scheduled for Thursday’s hearing.  According to prepared remarks, Califf will ask lawmakers for $76 million in new funding for food safety and nutrition. The request comes amid long-standing concerns that the FDA’s food program, which regulates most foods in the United States except meat, poultry, and eggs, is underfunded in comparison to the agency’s drug and medical divisions.

House Democrats passed a $28 million spending bill on Wednesday evening that would increase FDA funding for inspections of domestic and international formula manufacturers. Its fate in the Senate remains unknown.