Money Smithfield Foods pushes to quash subpoena in investigation of COVID-19 outbreak at South Dakota plant July 3, 2020July 4, 2020 Patrick Anderson, Sioux Falls Argus Leader Comments Off on Smithfield Foods pushes to quash subpoena in investigation of COVID-19 outbreak at South Dakota plant Smithfield Foods is asking the courts to intervene in a federal workplace safety investigation over a COVID-19 outbreak at Sioux Falls plant.