Almost 400 meatpacking plants in the United States have had outbreaks of COVID-19 as Aug. 19, according to Midwest Center for Investigative Reporting tracking.

However, only roughly half of those plants have been publicly identified, despite calls for companies and government officials to identify them all.

In June, Senators Elizabeth Warren, D-Mass., and Cory Booker, D-N.J., asked four major meatpacking companies to tally what plants had outbreaks and how many workers were infected.

The companies — Tyson, JBS, Cargill and Smithfield Foods — refused.

Other efforts to account for what specific plants have had outbreaks have been stymied.

Brown County, Wisconsin, officials told the Milwaukee Journal Sentinel they had stopped tracking cases tied to plants because it was time-consuming.

Virginia officials, though they released data on nursing homes, said they wouldn't do the same for poultry plants because of privacy concerns, according to the Virginia Mercury.

North Carolina, which has had the most plants with outbreaks, has also resisted releasing a specific list. Instead, it has released aggregate data for the whole state.