A meat processing plant in South Dakota has become the biggest single-source hotspot of coronavirus cases in the United States, with at least 518 employees testing positive for the virus and at least 126 non-employees contracting the virus through exposure to workers.

Smithfield Foods’ pork processing plant in Sioux Falls has overtaken the Navy ship USS Theodore Roosevelt, which has docked in Guam with at least 615 cases, and a jail in Chicago, with 524 cases, as the worst cluster in the country, according to data collated by The New York Times. It comes as South Dakota’s governor has resisted a statewide lockdown.

A team of Centers of Disease Control and Prevention health experts arrived at the Sioux Falls facility this week after the company announced on Sunday that it would shut down the plant indefinitely, weeks after confirming its first case. The plant, one of the world’s biggest pork production sites, has 3,700 employees, most of whom are immigrants, according to NPR.

The CDC team will work with state officials to understand the scope of the outbreak and figure out a plan for safely reopening the plant, said Health Secretary Kim Malsam-Rysdon.

South Dakota Gov. Kristi Noem, a Republican, said that Smithfield employees were being “aggressively” tested, as well as those who may have been exposed to them. However, Noem has been harshly criticized for resisting calls to implement a shelter-in-place order as the state’s coronavirus numbers surge, doubling roughly every four days. Confirmed cases in the state reached at least 1,168 on Wednesday.

“I don’t believe it’s appropriate considering the data, the facts and the science that we have,” Noem said on Tuesday. Meanwhile, Sioux Falls Mayor Paul TenHaken has been pushing for a lockdown order in his city to mitigate the fast spread of the virus.

He wanted an order to be issued county-wide, covering Minnehaha County and Lincoln County, which together account for over 1,000 cases in the state—but the governor rejected it.

TenHaken’s push for a citywide order has been met with resistance from city councilors, who have been overwhelmed by calls and emails from residents who vehemently reject the proposal, the Argus Leader reported.

“I don’t think it goes far enough. I don’t think it does anything,” Councilor Pat Starr told the Argus Leader. “If you’re going to do a shelter-in-place order, you’ve got to make people shelter in place, and this doesn’t do that.”

TenHaken, however, said the order would prevent the healthcare system from being overwhelmed and give authorities the ability to control “gross negligence and gross disrespect of the ordinance” by residents by fining them for leaving their houses unnecessarily, according to the Leader. “If we take it to the next level, which is what we’re proposing to our council tonight, we have a chance to cut our ICU bed needs in half at our peak,” he said.

Smithfield confirmed its first positive case of the virus at the Sioux Falls plant as early as March 26. While it reportedly added safety precautions at the facility to protect workers, such as hand sanitizer and frequent cleaning, it also offered staff a $500 “responsibility bonus” in April, which workers said encouraged them to keep coming into work, potentially putting their health and lives at risk.

“Because management drug its feet and didn’t act quickly, that’s why it’s a hot spot,” Kooper Caraway, the president of a labor federation in Sioux Falls, told the Argus Leader. “And we’re seeing the cases go up every day. No matter what the latest numbers are, I promise you there’s more than that.”

“I’m not a fool,” an unnamed employee told the Leader, referencing the $500 bonus. “Five hundred dollars isn’t worth our lives.”

Smithfield, however, claimed on its website that the bonus was “in recognition of an immense gratefulness for its employees’ dedication and performance during this time.”

The daughter of a plant worker who tested positive for the virus—who requested anonymity to avoid backlash from Smithfield—told The Daily Beast on Thursday that the company notified employees of the first confirmed case in March and told them that the plant would be shut down for a three-day period from Friday to Sunday to deep clean the facility. Her father, however, continued working at the plant and packaging meat during the supposed shutdown.

“There are so many families affected by this,” she said. “I wish they would’ve shut down when they said they would shut down. I saw that one man had passed away. Now I’m all worried and scared thinking what if that’s going to be my dad? I’m trying to be positive but I can't with this company.”

She feared that the company had dishonestly announced a three-day shutdown while still asking workers to show up.

After a push from TenHaken last week, Smithfield announced on Thursday that it would close the plant for just three days for sanitation after reports of a possible outbreak. Two days later, the number of infected workers shot past 100, prompting the mayor to write a letter to the company, demanding a two-week closure. He also shared the letter with Noem, who approved the proposal.

On Sunday, the decision was made to indefinitely shut down the plant, which subsequently forced the closures of another pork plant in Columbus Junction, Iowa and a top beef packing facility in Greeley, Colorado. Smithfield’s meat processing plant in Cudahy, Wisconsin was also shut down for two weeks after several employees tested positive, as well as the Martin City, Missouri raw meat plant, which was closed indefinitely.

Smithfield’s CEO Kenneth Sullivan released a statement on Monday that alluded to possible dissent within the company. “We have a stark choice as a nation: we are either going to produce food or not, even in the face of COVID-19,” he wrote, adding that the closure “is pushing our country perilously close to the edge in terms of our meat supply.”

His statement, however, was rebuked by Christine McCracken, an industry analyst and senior director for animal protein at RaboResearch, who told NPR that there is “still a lot of meat on the market.” “Quite a bit of meat actually; pork, chicken and beef,” she added.

Augustín Rodriguez, a 64-year-old Smithfield worker who was presumed to be the first confirmed coronavirus case at the plant, died on Tuesday after a 10-day battle against the virus. His wife, Angelita, told the Leader that he continued going to work even though he was experiencing symptoms consistent with the coronavirus.

“I lost him because of that horrible place,” she told the Leader. “Those horrible people and their supervisors, they’re sitting in their homes, and they’re happy with their families.”