U.S. Department of Agriculture officials have launched an internal investigation into how the agency handled reports of serious problems at a Boar’s Head deli meat plant tied to a deadly listeria outbreak, a lawmaker said Tuesday.

Sen. Richard Blumenthal, D-Conn., said that USDA Inspector General Phyllis Fong is looking into whether federal investigators and Virginia state inspectors responded appropriately to dozens of reports dating back at least two years of problems at the factory, including mold, insects, dripping water, and meat and fat residue on walls, floors and equipment.

At least 10 people died and nearly 50 were hospitalized in 19 states since May after eating listeria-contaminated Boar’s Head products. — Associated Press