The leaders of Emergent, whose factory spoiled vaccine doses, will testify before a U.S. House panel.

In a statement on Wednesday, the company said that it had responded to the F.D.A.’s observations with a “comprehensive quality enhancement plan” and had “already started making improvements.”

On a recent call with investors, Mr. Kramer announced a management shake-up and said that while the company had “implemented multiple layers of disinfection and other protocols to lessen the inherent risk of cross-contamination” when manufacturing two vaccines in the same plant, the precautions “did not function as anticipated.” He took “full responsibility” for the manufacturing problems that ensued, acknowledging that the “loss of a batch for a viral contamination is extremely serious, and we treated it as such.”

In letters to the two Emergent executives last month, Mr. Clyburn and Representative Carolyn Maloney, Democrat of New York and chairwoman of the House Oversight and Reform Committee, demanded a slew of documents, including any correspondence between the company and Dr. Robert Kadlec, President Trump’s assistant secretary for preparedness and response, who previously consulted for the company. In interviews, Dr. Kadlec has said his consulting work, in 2013 and 2014, was limited and did not affect contracting decisions.

“Emergent has been in the news a lot lately, and that’s frankly not something we’re used to,” Mr. Kramer wrote in a commentary posted on the company’s website last month. “Until a year ago we were a little-known company that does our work behind the scenes.”

The company is trying to burnish its image with television and digital advertising, as part of a campaign it is calling “We Go.” The 30-second ads feature images of white-clad lab technicians and spotlight some of the company’s lesser-known work manufacturing cholera vaccines and medicine used to treat opioid overdoses, as well as its Covid-19 work.

Emergent’s plant in Baltimore is one of two federally designated Centers for Innovation in Advanced Development and Manufacturing, funded in part by taxpayers. In June 2020, the federal government awarded Emergent a $628 million contract, largely to reserve space for coronavirus vaccine manufacturing, despite staffing and quality concerns.

The Biden administration responded to the potential contamination last month by putting Johnson & Johnson in charge of the Baltimore facility and moving out AstraZeneca. Doses made at the plant have not been cleared for use in the United States, and millions of shots made in Baltimore and sent overseas have also been put on hold.