Executives at contract vaccine manufacturer Emergent BioSolutions covered up quality control problems that led to more than 400 million doses of coronavirus vaccines needing to be trashed, congressional investigators said in a report Tuesday.

The number of destroyed doses was far higher than previously thought, and senior executives had been warned for years that its quality systems were deficient, according to the House committee report.

“Despite major red flags at its vaccine manufacturing facility, Emergent’s executives swept these problems under the rug and continued to rake in taxpayer dollars,” said Rep. Carolyn Maloney, D-N.Y.

The report said inexperienced staff and high turnover rates contributed to vaccine contamination.

The problem-plagued Baltimore factory was shut down by the Food and Drug Administration in April 2021 due to the contamination. The company was forced to trash what was thought to be the equivalent of tens of millions of doses of vaccine it was making for Johnson & Johnson. The bulk vaccine had been contaminated with an ingredient for AstraZeneca’s COVID-19 vaccine, which was being made in the same factory.

The U.S. Food and Drug Administration allowed Emergent to resume COVID-19 vaccine production in August 2021. Emergent received $330 million in taxpayer funds before the federal government terminated the contract in November, the report said.

Emergent’s chief executive, Robert G. Kramer, has apologized for “the failure of our controls” and blamed the factory’s problems on the complexity of scaling up production quickly on two different vaccines.

(AP)