One of America’s biggest pork processing facilities has shut its doors indefinitely after employees started falling ill with the novel coronavirus—and the company’s CEO has warned that the U.S. meat supply is now under serious threat. The facility in Sioux Falls, South Dakota, accounts for around 5 percent of the country's pork production and employs about 3,700 people, according to Smithfield, which runs the plant. “The closure of this facility, combined with a growing list of other protein plants that have shuttered across our industry, is pushing our country perilously close to the edge in terms of our meat supply,” said Chief Executive Kenneth Sullivan. “It is impossible to keep our grocery stores stocked if our plants are not running... These facility closures will also have severe, perhaps disastrous, repercussions for many in the supply chain.” South Dakota Gov. Kristi Noem said over the weekend that Smithfield employees accounted for more than half of the active coronavirus cases in the state. About 240 employees are sick, she said. Meat processors in Iowa and Pennsylvania have also shut down because of sick employees.