One of America's leading pig slaughterhouses is running faster than ever as meatpackers hustle to keep pork in grocery stores during the COVID-19 pandemic.

Plant worker Hector Ixquier believes it's time to slow down.

Ixquier said he sought medical treatment in January for tendons he strained in his right arm while draining blood from pigs in a Seaboard Foods pork plant in Guymon, Okla.

The 30-year-old immigrant from Guatemala said he requested a transfer to the position piercing jugular veins about five months ago, after an increase in slaughtering speeds made it too tiring to do his previous job: wrestling chains around pigs' hind legs before they are killed.

His new job is also physically taxing, and a doctor recommended rest and avoiding certain tasks at work, Ixquier said. "I'm thankful for the opportunity," he said of the new gig, "but it's still too fast."

Seaboard, the second-biggest U.S. pig producer after Smithfield Foods, sped up its Guymon operations last year after the U.S. government removed limits on pork plant line speeds in late 2019. It was the first plant to operate under the new rule, which was intended to allow processors to produce meat more quickly.

But some workers, such as Ixquier, said they have suffered physically as a result. Seaboard now requires employees to slaughter between about 1,230 and 1,300 hogs per hour, two plant workers who are also union stewards told Reuters. That compares to under 1,100 an hour in 2019, said one of the workers, Jose Quinonez.

Workers and their advocates said the rule change is part of a series of measures finalized by former President Donald Trump's administration that jeopardize employee safety, including exempting dozens of poultry plants from slower line speeds and reopening plants battling COVID-19. The changes, and prevalence of COVID-19 at slaughterhouses, have made it harder to keep workers in their jobs at a time when U.S. companies are trying to build up meat supplies.

Seaboard, which didn't respond to questions about Ixquier, said employee health is a top priority. The company, a subsidiary of Kansas-based Seaboard Corp, works to improve processes and equipment and hires additional employees to help ensure each worker's load is manageable and safe, said Seaboard spokesman David Eaheart.

Eaheart added that the rule relaxing pork line speed limits improves Seaboard's ability to adjust operations based on demand. Seaboard aims to average 1,200 pigs per hour under normal conditions, but has adjusted speeds as the pandemic has reduced staffing, he said. The company needs to examine how the plant will work under non-COVID-19 conditions to "truly understand" how the change affects it business, Eaheart said.

Under the new rule, pork plants can slaughter as fast as they want, as long as they prevent fecal contamination and minimize bacteria. Previously, the government-imposed limit was 1,106 pigs per hour.

President Joe Biden's administration, which pledges to prioritize worker safety, withdrew a Trump-era proposal to allow all poultry plants to operate faster. But reversing the pork rule would be trickier, lawyers said, because it is already in effect.

The 2019 elimination of pork-line speeds by the U.S. Department of Agriculture was part of the New Swine Inspection System, which also lets pork plants use some company inspectors instead of USDA ones.

The Seaboard plant in Guymon last March became the first to operate under the new rule, according to USDA documents. Before the rule change, six other major U.S. pork plants had surpassed the previous slaughter speed limits with special USDA permission. The USDA told Reuters that the slaughterhouses had demonstrated they were capable of producing safe pork while operating at faster speeds.