The union that represents workers at a Vernon meatpacking plant where at least 153 have come down with COVID-19 called Monday for the immediate closure of the facility, saying there was no evidence measures taken to control the coronavirus were working.

The outbreak at the Farmer John plant, a division of Smithfield Foods that produces Dodger Dogs and other pork products, is by far the largest in Los Angeles County to occur outside of a nursing home, prison or other residential setting, according to data from the county’s Public Health Department.

The union that represents most of the plant’s 1,800 employees alleges that the company delayed rolling out protective measures until workers were sick and has not been transparent about what it knows about how and to whom the virus is spreading within the facility.

“Smithfield has not provided full information about what is really going on inside the Vernon plant,” said John Grant, president of UFCW Local 770. “Without information we cannot make an informed decision about workers’ health and safety.”