Some 2,800 United States Postal Services workers have tested positive for the coronavirus, forcing the federal agency to hire replacements and worsening an internal financial crisis that could stamp out the government service.

House Homeland Security Chairman Bennie Thompson, a Democrat from Mississippi, said that 4,000 USPS employees have been directly impacted by the virus. On top of the 2,800 confirmed cases, 1,200 workers have unconfirmed cases, Thompson said during a virtual hearing with packaging experts Wednesday afternoon.