At least 59,000 meatpacking workers contracted the coronavirus in the first year of the pandemic as the virus rapidly spread in plants’ cramped conditions, according to internal documents from five major meat conglomerates obtained by a U.S. House subcommittee investigating the coronavirus response.

The panel’s findings offer greater detail on the virus’ toll among a largely immigrant workforce that managers implored to keep showing up for work as much of the rest of the country shut down, often in massive plants that employ hundreds or thousands of people working elbow-to-elbow along fast-moving production lines. At least 269 meatpacking workers at the five companies died from COVID-19 between March 1, 2020, and Feb. 1 the following year, the panel reported on October 27.

The report by the Select Subcommittee on the Coronavirus Crisis cites interviews with staff members of the U.S. Occupational Safety and Health Administration saying that leaders of the agency made “a political decision” in 2020 during the Trump administration not to issue a regulatory standard that would have required meatpacking companies to take specific steps to protect workers.

The committee staff cited examples of individual plants where infection rates soared as high as 54% of the workforce at JBS SA’s facility in Hyrum, Utah, and 50% at Tyson Foods Inc.’s plant in Amarillo, Texas.

At the Amarillo plant, employees as late as May 2, 2020, were working in masks “saturated” with sweat and other fluids and separated only by flimsy “plastic bags on frames” rather than barriers, according to memo from local and federal authorities to Tyson Foods obtained by the subcommittee.

A U.S. Department of Agriculture report issued in September pointed to the closer working conditions in meatpacking plants than other U.S. manufacturing facilities as a likely reason the industry became an early epicenter of the pandemic. The 49 rural U.S. counties most dependent on meatpacking plants for employment had COVID infection rates 10 times the level of other manufacturing-dependent rural counties in May 2020, the USDA found.

The subcommittee’s coronavirus findings were based on internal documents from JBS, Tyson, Smithfield Foods Inc., Cargill Inc., and National Beef Inc.

The totals are likely an undercount since in many cases they don’t include COVID infections detected through off-site tests or cases self-reported by employees, the committee staff said.