The U.S. Labor Department has cited Smithfield Foods and JBS for failing to protect employees from the coronavirus, making them the first two major meatpackers to face a federal fine after outbreaks at slaughterhouses infected thousands of workers.

The citation did little to quiet complaints from labor unions and safety advocates, who said the Trump administration needs to do more to protect workers critical to the nation's food supply.

Both JBS USA and Smithfield said the citations were without merit.

The Labor Department's Occupational Safety and Health Administration (OSHA) proposed fining Smithfield $13,494 and JBS $15,615.

The companies have until about the end of the month to respond and put into place safety measures.

OSHA cited Smithfield's plant in Sioux Falls, S.D., for "failing to provide a workplace free from recognized hazards that can cause death or serious harm," according to a statement.

At least 1,294 Smithfield workers contracted the coronavirus and four employees died this spring, OSHA said.

The JBS complaint stems from an outbreak at the company's plant in Greeley, Colo., where 290 have tested positive and six have died.

The citations issued to the companies said employees worked close to one another and were exposed to the virus.

They come as companies face increasing litigation over worker infections and mounting pressure to protect front-line employees.

In connection with a COVID-related inspection in Minnesota, the state's OSHA has already fined JBS $28,000 for what it deems four "serious" safety violations at the Pilgrim's Pride chicken processing plant in Cold Spring, Minn., and another $29,400 for five violations at the Worthington pork plant.

JBS USA, which owns both plants and is owned by the Brazilian meat giant, is contesting the citations. OSHA is also investigating several COVID-related fatalities, including investigations opened in May and June into two fatalities at the JBS pork plant in Worthington.

Critics of the more recent action by the federal OSHA said the Smithfield penalty was too small.

"It's not even a slap on the wrist," said David Michaels, a professor of environmental and occupational health at George Washington University, who served as U.S. assistant secretary of labor for OSHA under the Obama administration.

"After 1,300 workers have been infected, dozens hospitalized and four killed, a small fine like this sends the message to Smithfield and other meatpacking companies that they have no reason to worry about OSHA."

The Labor Department said in a statement that OSHA was committed to protecting workers and cited Smithfield in accordance with well-established procedures and legal standards.

As far as the JBS plant, OSHA Denver area director Amanda Kupper said the agency has industry guidance and other resources to assist in worker protection.

"Employers need to take appropriate actions to protect their workers from the coronavirus," she said.

But JBS spokesman Cameron Bruett said the citation "attempts to impose a standard that did not exist in March as we fought the pandemic with no guidance."

In late April, he said, when OSHA issued its first guidance, JBS' preventive measures "largely exceeded" what was required.

"We have implemented hundreds of interventions to protect our workforce," Bruett said, including health screenings, staggered start times, mask-wearing and physical barriers.

JBS believes the Greeley facility is in full compliance with the recommended guidance.

The Greeley facility, he said, has only had 14 confirmed positives in the past 3½ months, representing 0.4% of the workforce there, and has had no cases in nearly seven weeks.

Smithfield, owned by China's WH Group Ltd., also thinks the citation is without merit and plans to contest it, spokeswoman Keira Lombardo said.

The company has taken steps to protect employees and spent $350 million related to COVID-19 during the second quarter, she said.

In July, Smithfield sued OSHA in a bid to quash a subpoena issued as part of a federal probe into the plant. The two sides ultimately came to a resolution, and the case was dismissed.

"The fact is that the Sioux Falls community experienced an early spike in COVID-19 cases, which impacted our plant," Lombardo said.

Nearly 20 meat plants run by companies such as Smithfield, Tyson Foods Inc. and JBS USA closed temporarily this spring because of outbreaks. These included JBS' Worthington pork plant and its Pilgrim's Pride chicken plant in Cold Spring.

JBS could not immediately be reached for comment.

President Donald Trump in April ordered plants to stay open to protect the U.S. food supply, despite concerns about outbreaks, drawing a backlash from unions that said workers required more protection.

"The failure by the Trump administration to hold Smithfield accountable makes clear that this White House cares more about industry profits than protecting America's essential workers," said Marc Perrone, president of the United Food and Commercial Workers International Union, America's largest meatpacking union.

California's state OSHA this month cited two smaller meatpackers, one frozen-food manufacturer and eight agriculture or farm-labor contracting firms, after the agency determined the companies failed to protect employees from COVID-19.

Cal/OSHA proposed over $200,000 in penalties each to food manufacturer Overhill Farms Inc. and its temporary employment agency Jobsource North America Inc.

Overhill disputed Cal/OSHA's findings and said it would contest them. Jobsource could not be reached for comment.

"It has been scary working through this pandemic and watching co-workers get sick while wondering if I will be next," Overhill worker Hilda Morales said.

Star Tribune staff writers Adam Belz and Catherine Roberts contributed to this story.